Will this PSU work?

i have a dell inspiron 530 (0ry007 mother board) and it has the stock 300 Watt psu with a 8600 GT graphics card, but i would like to do some upgrades and put in at least a GTX 260, or maybe 275, i have found this 550 W PSU to replace my current one http://www.bfgtech.com/bfgr550wgxpsu.aspx here r the specs:

> +3.3V = 22A
> +5V = 15A
> +3.3V +5V Max. Combined Wattage = 130W
> +12V1 = 18A
> +12V2 = 18A (so yes its dual rail)
> +12V Max. Combined Wattage = 404W
> -12V = 0.3A
> +5VSB = 2.5A

so i was wondering, will this do the job and allow me to have a gtx 260 or 275? ( BTW i have a core 2 duo E6550)

the main thing that im wondering what exactly is the -12V ? my consern is the -12V, because my current PSU has a -12V of 0.8A and the PSU i want is 0.3A, than and the =5V on the one i want is less than the current one

specs of current PSU:

> +5V = 22A
> +3.3V = 17A
> +3.3V +5V max combined wattage = 160W
> +12V = 18A
> - 12V = 0.8A
> +5Vs = 2A
> Total Max power 300 W

well, i was thinking that BFG one cuz i can pick it up locally at a store, but i was also looking at this one http://www.tigerdirect.ca/applicat [...] etailspecs cuz its a good price and seems good, but once again, my only concern with it is that the -12V is below my current one, even with everything else on that PSU that good, so can i maybe get some one to explain the whole -12V thing to me, and the advantage of having more or less, which is better,

well, i was starting to look at this one, even better http://www.tigerdirect.ca/applicat [...] CatId=2533

well idk about for shipping, but it says its 5 bucks less on TD