Forget getting any BTC this way.
Look here:
https://bitcointalk.org/index.php?topic=259649.0If you mine in this multipool, you will mine other Scrypt coins - those easily mineable with GPU.
That multipool will convert all earnings to BTC and send it to you.
Still, you will earn one BTC much faster this way than in ordinary BTC pool.
Not sure how much faster, but I think about 1 or 2 years for 1 BTC.
Although you have nvidia card, not as good as ATI cards for mining.
With good ATI card you may be able to earn 1 BTC maybe in 2-3 months.
Directly mining some other new experimental coins can be even more profitable.
But you have to know the coins.
And even then there is a risk - you may mine coin that later just dies, without any profit.
So stick with the multipool I suggested.
At least until you learn more about Altcoins and mining.
And if you want to mine bitcoin directly, you can get some good ASIC.
CPU's, GPU's and bad ASIC's are just waste of power and money.
But good ASIC's are expensive (one costs several BTC).