Sorry, I've not been to Cordoba but here are just a few pointers to get you started in your quest for information:
Train services between Granada and Cordoba are very limited, with just two direct trains per day. (One morning service and one evening one. Journey time = approx 2 hours 20 minutes). At other times you'd have a two-train journey, totalling between 4 and 5 hours.
On one of the rare days when RENFE's website is actually working, you might be able to check train times here:
http://www.renfe.com/EN/viajeros/index.html
However Die Bahn's website is far more reliable. (It can plan any rail journey in Europe for you, including those across national borders):
http://www.bahn.de/i/view/GBR/en/index.shtml
There are 8 direct bus journeys per day between Granada and Cordoba. Most journeys take around 2 hours 40 minutes. The single fare is €12.60. (€22.73 return):
http://www.alsa.es/portal/site/Alsa/
This appears to be the best website to learn about Cordoba's attractions:
http://www.cordoba24.info/english/
Chris