You're fine the power requirements for that card are low.
Easily under 200w in real world conditions.
Single GPU 5670
System in IDLE = 164 Watts
System with GPU in FULL Stress = 222 Watts
Difference (GPU load) = 58 Watt
Dual GPU 5670
System in IDLE = 175 Watts
System with GPU in FULL Stress = 285
Difference (GPU load) = 110 Watt
Thank you very much for replying
so does this mean I will not need to upgrade my PSU anytime soon? I also heard that a big monitor takes up about 80 watts. I'm kinda concerned about this. I want to make sure that nothing goes wrong.