Can my PSU run GTX 260+ OC?

[hai12345]

I just got the GTX 260+ OC edition by Galaxy and I,ve read that the gpu needs at least 500w of power supply with 38A on the 12v rail. I have a Thermaltake Power Supply Litepower 550w Black Edition (W0424RB) with 24A on 12V1 and 21A on 12V2. Will this be enough since I read some articles stating that the 12V rail produces lower power than the one said on the sticker?

My Specs :
GA G41M Combo with Intel Core 2 Duo E8400
4gb of ddr3 ram
160gb hdd

Thanks.