***help required with sky tv please***

hi all
just taking on a holiday home in villamartin. stayed there in the summer and there is a satellite dish fitted and sky box in the lounge. we could only get sky news and about 5 or 6 rubbish channels and some radio stations with their ancient sky card inserted.
im told that if i bring out my sky card from uk and leave it in the sky box in spain for up to 24 hours i will get many more channels. in fact my brother -in law does this when staying at a friends place in mazarron.
does anyone know if this works everywhere??
if not, considering i have already got suitable equipement fitted, how difficult / expensive will it be to get a decent set of channels (to include bbc1 itv etc)??
many thanks for any info you can provide me with.
tony.