With that power supply, I'd be looking at a 750Ti/R7 260X tops. So, forget about the GTX480, unless you plan on spending 60€ on a decent 550W unit.
The thing is, both those games are very demanding when it comes to graphics and, right now, you have a card that is an intel integrated chip replacement. It's a really bottom-line card, good for everything...except 3D games from 2004 onwards. Both the alternatives you listed, the GT625 and the GT610, are pretty much the same. Like it has been said here, gaming graphics cards start at ~150€. Also, start looking for local computer hardware shops, or amazon. Leave ebay unless you know what you are doing.
Going by the board and the PSU, I know where you got the parts. Not gonna judge, but....yeah, a_ump said it right.