Hi,
Realistically CPU and GPU mining aren't anywhere near worthwhile now.
At 300 Mh/s you may make 20 cents a day which won't come close to paying for the 150w+ needed to run your GPU. You can get an Asicminer USB block erupter for under $20 which has the same hashrate as a fast GPU but only takes 2.5W of power, but even with this you are unlikely to break even IMHO.
Have a look on ebay for "ASIC Bitcoin" or "Bitcoin miner" to see some options.
Cheers,
o999.
I actually dont have to pay for any energy usage so that isnt an issue, but i understand that its a snails pace, and at those numbers more for fun and seeing how much I can output.