That's a very, very broad question. Hopefully I can give you some tips. :) However, please don't go out and buy a new card straight away - there are almost always software options to try first, and they're worth trying if they save you that much money! I'll provide this info in case you do end up going for a new card anyway, but that doesn't mean I think that's necessarily the best solution - I just don't know what the other ones are. :)
The first important question is what you use the computer for. If Ryzom is the most taxing thing you play, save your money and get a cheap card - one of the old nVidia models with a 4-digit model number, even, if you can find one new; or a GTS. Ryzom really can run on peanuts. If, on the other hand, you're a more dedicated gamer type playing new games, or you do graphics-heavy work like 3D animation, it's worth paying extra for a nice, futureproof card. Or you might be somewhere in between the two extremes. :)
It's also important to think about your other specs: what're your CPU and RAM? There's no point buying a great card if it's bottlenecked by another component which you don't intend to upgrade at any point. This is the point at which I thank Ma'Duk that everything is PCI-E now and we no longer have to give a hoot about slots. >.>
I hope you're on a regular desktop, not a laptop, slim tower, or All-In-Wtfisthis?
Forgive me if you know this already, but it's useful to understand GeForce model numbers:
The second number is more important than the first. A 480 is better than a 560, even though the 560 is newer. This isn't an absolute rule applicable in every situation, though.
The letters also very important. If you're a heavy gamer, you don't want a GT, ever. In order of strength, it goes GS -> GT -> GTS -> GTX, though the first two may no longer be in use - I haven't seen new GT or GS models in a while, anyway. The difference is significant enough that you're often better off going two generations (e.g. 9xxx -> 7xxx) back, to get a GTX in the lower series rather than a GT in the higher one.
You may find these useful:
http://www.tomshardware.com/reviews/gaming-performance-radeon-gef orce,3018.html
http://www.tomshardware.com/reviews/gaming-performance-radeon-gef orce,2997.html
http://www.tomshardware.com/reviews/best-graphics-card,2964.html
The comparison charts in the last section of each article are particularly useful. I use them to translate Radeon model numbers into a language (GeForce) that I understand. :P Remember that Google is also very much your friend. ;) There are tonnes of reviews out there for pretty much any card you might consider, and they're well worth a read.
Lack of specific suggestions, I know, but they're hard to give without knowing your current specs and what you need from a new card. :)
The first important question is what you use the computer for. If Ryzom is the most taxing thing you play, save your money and get a cheap card - one of the old nVidia models with a 4-digit model number, even, if you can find one new; or a GTS. Ryzom really can run on peanuts. If, on the other hand, you're a more dedicated gamer type playing new games, or you do graphics-heavy work like 3D animation, it's worth paying extra for a nice, futureproof card. Or you might be somewhere in between the two extremes. :)
It's also important to think about your other specs: what're your CPU and RAM? There's no point buying a great card if it's bottlenecked by another component which you don't intend to upgrade at any point. This is the point at which I thank Ma'Duk that everything is PCI-E now and we no longer have to give a hoot about slots. >.>
I hope you're on a regular desktop, not a laptop, slim tower, or All-In-Wtfisthis?
Forgive me if you know this already, but it's useful to understand GeForce model numbers:
The second number is more important than the first. A 480 is better than a 560, even though the 560 is newer. This isn't an absolute rule applicable in every situation, though.
The letters also very important. If you're a heavy gamer, you don't want a GT, ever. In order of strength, it goes GS -> GT -> GTS -> GTX, though the first two may no longer be in use - I haven't seen new GT or GS models in a while, anyway. The difference is significant enough that you're often better off going two generations (e.g. 9xxx -> 7xxx) back, to get a GTX in the lower series rather than a GT in the higher one.
You may find these useful:
http://www.tomshardware.com/reviews/gaming-performance-radeon-gef orce,3018.html
http://www.tomshardware.com/reviews/gaming-performance-radeon-gef orce,2997.html
http://www.tomshardware.com/reviews/best-graphics-card,2964.html
The comparison charts in the last section of each article are particularly useful. I use them to translate Radeon model numbers into a language (GeForce) that I understand. :P Remember that Google is also very much your friend. ;) There are tonnes of reviews out there for pretty much any card you might consider, and they're well worth a read.
Lack of specific suggestions, I know, but they're hard to give without knowing your current specs and what you need from a new card. :)