i would suggest getting a new PSU with a higher Amps because it might not be enough to supply for your graphics card.
You can run the Extreme PSU Calculator, and see how many Watts your computer needs, and if you are willing to pay $2, then it will tell you how many Amps you need to.
yeah...basically if everything is working normally then you are fine.
remember, if you aren't getting enough power to your hardware...it doesn't damage it...it simply won't run properly...because of the lack of power. So if you notice things stop responding...or things not running at their full capabilities...then you know you have some power issue. Otherwise...you're fine