I'm sorry to give you the bad news, but... unless you're part of a pool with that card, you have about a 50% chance of solving a single block if you mine for half a year (180 days). When you solve a block, you get the entire reward (25 coins). But again... if you do it for 180 days, you have about a 50/50 chance of getting anything (very roughly). But either way, you'll be paying for that electricity... :)