There's not much point using Movistar if you are going to be in Gib. Try Gibtelecom.
They do different packages so check out their website, which is pretty comprehensive. Other providers are Sapphire and CTS.
I have an iPhone and use Gibtel, which also works in the surrounding area of Spain, and then I switch to vodafone, when I lose coverage. You can do contract or PAYG with Gibtel.
Gibtel can be helpful but ring in office hours if you have a technical query.
Hope that helps.