Hi Dave and welcome to the forum.
There is a certain irony in your situation as we struggle to get RHD light at a good price in the UK for conversion.
I wouldnt worry too much about the US light, we but a lot of bits from there.
First suggeston, get some of those cheap shades in the meantime. Have a word with Adam from Z1Auto who is a US trader on this forum. Alternatively, and I will check, I thought we had an american owner moving over here with his car in the near future, he may do you a swap.
Paul T from Dream Customs, also a trader on here may also be able to help.
Changing the headlight isnt that bad, there is a guide on here.
Lastly, where in Spain are you, I am over there from time to time but the pot holes scare the hell out of me.