What powersupply do I need?

Specs:

AMD athlon 64 x2 dual core 6000+ 3.0 gz
3 gig ram
DVD/cd burner
DVD driver
sata hard drive
8600 gt vid card
500 watt supercore powersupply

Problem, I recieved a gforce gts 250 for a surprise present, brand new. When I plug it it, the power to both my cd drives is lost, but the card works perfectly. If I unplug one of the cd drives, I'm back in business but scared I am pushing things too much?

Everyone tells me 500 watts ps should be plenty, but from a little research here, all things aren't equal, I need to make sure enough power is to each rails or something?

I plan to limp along with this system for the next 6 months or so, until getting a mb/processor of a quad core variety or something. So with an upgrade in mind, what power supply do I need, or will this one work if I buy some adapters to move some of the components off of using one "rail" too much or something?

Now If I am happy to just unplug the dvd burner that I never use, as I stressing something too much?