Aston University is situated around the City Centre, it is extremely unlikely there are any free parking spaces around it ( I've never seen any, although i've never been on the hunt) and inside Aston, i am unsure. I have seen plenty of staff parking, no student parking. In my opinion, keep your car at home. Travelling around Birmingham City Centre in a car is a lot more trouble than it's worth, believe me. I've lived there all of my life. An alternative would be to park your car in Aston/Erdington somewhere and catch the train to your car, I don't advise that either. I know too many people who have had to deal with robberies.