Guessing you're into keeping healthy, and if you're into beaches, then I'd suggest you're better off where you are i.e. Costa Blanca: the beaches in Torremolinos don't compare, and the water is anything but healthy - I wouldn't swim in it. 
Decent long term rentals aren't easy to come by. Word of mouth & personal contacts are the best way, but you could try talking to Cesar at DelSol Inmobiliaria, he may be able to help. Like any agency, they'll require references, deposits etc.
If there's anything specific I may be able to help with, feel free to ask.