We need a shower to give hot water and good pressure for spanish house with only cold water tank on roof, its very confusing. We DO NOT have any hot water at all in the house.

Not to be flippant but obviously you are going to have to install some kind of water heater. By spanish house do you mean a house located in Spain. That might sound like a dumb question but then you might mean a certain style of house or a house used in a certain way.

You are not being ignored, its just that if you mean a house located in Spain we probably don't know enough about local plumbing practices or utilities to help you.