You will never solo mine a bitcoin since your card would have to solve an entire block and then you would generate 25 bitcoins at all once. Graphics cards are way to slow at current difficulty to solo mine, so if you want to get involved with bitcoin, then join a pool.
Is it worth mining bitcoins with a video card? Simply put, no. But it could be fun and is a great way to learn how to use a pool, send and receive bitcoins etc. You could also buy a few of these
ASIC Miners and start a little bitcoin farm. Each of these miners roughly has the power of 1 video card in terms of mining bitcoins. Will you make money off them at current USD/BTC conversions? No. But once again it is a good introduction to bitcoins.