I know that this does not answer your question, but I am going to say it before the others do. ASIC is going to make your miner non profitable. If profit is your goal you are going about it wrong.
What he said, your card will only generate 200-300Mh/s at best, the new ASICs will generate 4.5GH/s or billion hashes for about the same price as that card at the fraction of the electricity cost. You will most likely only make .03 to .05 bitcoins a day if in a pool.
If you're doing it for fun then you can use these:
Aggression=11 GPU=950 MEM=800 don't know if these work in guiminer but they work in CGminer.
https://en.bitcoin.it/wiki/Mining_hardware_comparison#AMD_.28ATI.29 This link provides information on almost all mining hardware currently out. Including specs and some configuration tips.