No, you cannot see the entire country of Spain in two weeks.
You also have to understand the words "north and south" are very general, and encompass multiple regions of the country.
I actually lived, worked and went to the university in the region of Castilla-Leon, so I have a special fondness for this part of the country more than any other. I think that the Spanish language here is very rich, the area is quite historic and unique, and it is a bit more off the tourism path. My favorite cities in this part of the country include Santiago de Campostela (actually in Galicia, further north), Madrid, Segovia, Avila, and Salamanca. Toledo, in La Mancha, is another one of my absolute favorites. I could spend a week just visiting all the castles and cathedrals.
In the South, I love Sevilla, I find Cordoba quite sweet, Granada is a must-see because of the Alhambra, and yes, Ronda, Malaga, and Cadiz are all worth a visit. I also like the remoteness of Extremadura. Then there are beaches and beaches!
On the East coast, Valencia and further north, Barcelona, are also very popular with visitors.
You need to learn about all of these places and decide what truly interests you and what is a must-see. You have to consider your budget and your transportation--car or train? Then decide on your priorities and map out a route. Usually I choose to stay in the special castle/monastery hotels called paradores, so I map my trip out using their locations as bases.
The goal should not just be to create a check-off list of what you quickly see, but to create a meaningful and special trip that introduces you to the true heart and soul of the country, with all of its mighty history and special cultural components.