Mining bitcoin on graphic cards is not efficient anymore. You need ASICs that have hashrates of hundreds of GH/s and above to mine fractions of a bitcoin; you wouldn't break even in a month or even a year. I did my study of mining crytocurrency; purchasing an ASIC miner today will ship and reach you in 4 months. At that time, the difficulty would be so high that your miner renders useless. Forget about mining bitcoin.
What I did is move to other cyrto currencies; then exchange them for bitcoin. I experimented mining litecoin, but the difficulty is rising quickly. It is scrypt based, so high end AMD Radeon cards should be able to give decent hashrate (the 280X has the best hashrate/price ratio). Though even with 4 of these cards (can make around 3000KH/s), mining litecoin isn't getting profitable much (especially after litecoin's drop in price, was 30$ now 17$).
Thanks to cysto, I moved to Dogecoin (another cyrtocurrency). Dogecoin's difficulty level is still low, so mining it is pretty acceptable. I'm mining it with a total power of 490KH/s and have mined 14000 of it so far. According to
http://www.coinwarz.com/cryptocurrency, mining Dogecoin is profitable. At a mining hashrate of 3000KH/s (for example), it takes only 16 days to mine enough Dogecoin to make a bitcoin (versus 30 days with litecoin).
Consider moving on with mining Dogecoin; it is your best chance in making profit. Hope you have a decent AMD radeon card; happy mining!
