Doe the sticker look like this ( http://www.ebay.com/itm/DSAII450S-G-Channel-Well-Technology-450W-20-24-Pin-ATX-Power-Supply-/140816845883?pt=UK_Computing_PowerSupplies_EH&hash=item20c9568c3b
) with 2 +12v ratings listed at 17A each . . . if so that might be pushing it a little bit but should work.
The trouble I think you will have is that if it's a dual rail design like then each rail can only supply 204 watts individually, and only 360 watts total between the two rails. You will probably be pushing somewhere near 270 watts and depending on how the connectors are connected to each rail you may end up overloading one if you need to use a Molex->PCIE adapter (since you will need 2 PCI-E cables).
It might be worth it just to upgrade it to a more reliable and trusted brand somewhere in the 500-600 watt range just to be sure even if it is working since you will be pushing near the capacity of one of the rails which generally isn't considered standard operation, you would normally want to be under about 75% of it's rated capacity (shooting for 50-75% so you have lots of headroom).