Hi
Try La Torre. There are loads of rentals and reasonable price. You can normally rent per night. Also, its only 5 mins from head office.
Try www.holidayrentals.co.uk look under Murcia/Costa Calida then Polaris World resorts.
Also, owners direct and daltons have lots of rentals in Murcia.
Hotel Costa Narejos always has good deals and is just off the beach in Los Alcazares. Web site is www.hotelcostanarejos.com Well placed to walk to beach, bars and restaurants. About 15 mins drive from head office. There are lots of apartments to rent in los Alcazares also on the above web sites.
Good Luck!
Regards