US laptop

Hi my sister brought me back a laptop from the US. A toshiba A105. Problem is it has a US power supply. Went in to PC World but they wanted to charge me £70 for a British power supply thats just a rip off! I thought all I'd need is a power transformer or something similar is this right. I don't want to fry my new laptop.

Thanks

Why not just get an international adaptor for the wall socket?

Itll definately be switchmode, so a new cable will do, head down to maplin, shouldnt cost more than a fiver.

Yeah i think it is it says on the power brink 100 -240v.