HI, JILM
I am sure if you ar eu citzen, that to obtain residencia is easy now, all you should have to do is go your local townhall, with you nie number, or dni here both the same ask for the certificatado de residencia, you might have to be on the empadronata for the town hall, thats just to register yourselves at the townhall, then they will issue you residencia certifcate, the cost is usally between 4 euros to 13 sometimes its even free, it all depends where you are ant what townhall your under. Hope this helps and welcome.