I bought what I thought was a R2 with 330w PSU

So I bought the X51 second hand rather cheap. I assumed the R2 versions all come with a 330w supply. The lad I bought it off also said it was a 330w PS. I then picked up a second hand 1060 3gb card on the same day. Installed the card, booted up, all working, running PUBG. I brought the comp back to my base (military guy) and now the comp has started cutting off completely when playing PUBG, I was wracking my brains trying to figure out the problem and upon checking closer, I actually have the 240w PSU model...

Where does this leave me? Can I simply buy a 330w power brick and crack on?

Can I undervolt the card so it uses up less power?

Any help much appreciated.
Also, is there any place in the UK that stocks them at a reasonable price? Seems they cost £50+ pretty much everywhere and that's shipping from China...
if You use Dell, request military discount too.
I don't want to say for sure about the power board. Maybe someone Here can help you with that.
I believe the R2 versions all have the upgrade power board. But I am not Positive
Cheers for the replies. Anyone have a definite answer on whether the r2 is 100% compatible with a 300w psu without having to make any changes/upgrades to the mobo?
So, I finally got the 330W PSU. Played PUBG for a few games on mostly Ultra, using a custom fan curve. No crashes, No black screens or cut off. Im really chuffed with it. GPU maxes out at 82 degrees (using a dual fan Inno3d 3gb GTX 1060) and CPU maxing out at 63 degrees (Its a i5 4430). It runs PUBG so smooth on my 144hz monitor. So I can confirm that upgrading the 240W PSU to a 330W PSU is enough to play nice with a 1060.

I originally got the X51 for £120 , R2 model, 1TB 7200 HD, i5 4330 + GTX 645. Also got the 1060 for cheap before the crypto GPU nightmare inflated prices. Managed to flog the 645 and 1TB HD for £50 for both. Then bought a 256gb SSD and also took out the DVD drive.

All in all, I've got a really decent small form beast of a comp for actually rather cheap. Now I think I'm gonna paint the side panels white :)
Sent it back to seller via ebay so will hopefully have a replacement ASAP. I have also been offered a swap for my X51... for an Alienware 15 R2, 980m, i7 4720, 16gb RAM, 2xSSD... What do you all reckon? Aint had any experience with the 15 R2 laptops...