Flights and rental cars
The nearest international airport is Malaga (30min driving distance). In some cases it could be interesting though to look for a flight to Jerez de la Frontera (about 2 hours driving distance).
Have a look at the following pages for budget flights:

www.opodo.de
www.tripadvisor.de
www.airberlin.com
www.ebookers.at
www.edreams.de
www.expedia.de/fluege
www.billigflugzentrale.de
www.iberia.com/de
www.lufthansa.com

Information about Malaga airport (AGP):

www.expedia.de/destination/
www.aena.es/csee/

We would recommend renting a car at the airport (about 80 Euros per week). Ideally you could order a car via the internet; pick up the car at the airport when you arrive and drop it off the day of departure (some of them also offer children`s seats):

www.billiger-mietwagen.de
www.amigoautos.net/
www.expedia.de/mietwagen/
www.holidayautos.de/buchen/
www.mietwagen-in-spanien.de/