can you post back with your system specs please? we can advise you what GPU to get according to the power that you have hiding in that mobo.
You can pick up better cards with that amount of money + if you plan on getting a system upgrade then you have the (new) GPU to carry over to the new build.
can i buy a nvidia gddr 3 graphic card? it will fit?
the first answer, yes you can buy a DDR3 GPU
second, we don't know what case you are running your current system in. Thats why we need to know entire system specs. usually thread posters have slim cases that cause conflict with a purchase after consulting with techxperts. So to avoid such problems ... you get what i mean right ?