I have a Amazon affiliated beauty website how to transfer revenue from $ to £?

I have a website that i have been building is a beauty site http://www.lustforbeauty.com/ that is aimed at the US market and hence the revenue used is US $ but the trouble that i am having is i am based in the UK and when i get my commission i have trouble transfering the money into my sterling account.Yes it is not a problem as i have been doing it this way for many months but the revenue is reduced by a small amount every time my bank transfers the funds over this is due to currency transfer and also a small charge from the bank for the transfer.

So can anyone one suggest a way that i can get around these additional charges as the amount of visitors that i am getting to my site is growing at a fantastic rate and of course the charges will increase pro rata or certain help me reduce them so that i can keep more revenue.The obvious way would be to do away with the US store and have store based in sterling,yes i would do away with all charges but i would also see a massive drop in visitors and hence revenue.

Thanks