The following links may be useful:

If you wish to hire a car while in Spain, then I can make recommendations

If you don't wish to hire a car, then from Gibraltar, a taxi will cost about 40 euros.  If flying to Malaga, the best way is probably to get the non-stop coach from the airport to Marbella and then a taxi from there (about 60 euros) or if there are only 3 of you I may be able to pick you up.  If flying to Jerez, then it is  best to hire a car and enjoy the beautiful road across.