Well -- I think you better take your paperwork into the lawyer who represented you on the case or consult with a new lawyer if the first is not available. I don't think you should give up but just be smart about it and get good advice.
If you pled to a straight felony, it probably cannot be reduced. I would expect that your lawyer talked to you about all your options and the consequences of the plea at the time. if not, you might have a remedy now (not likely, but worth exploring with a lawyer).
Expungement is not expungement in California. It is a petiton for Relief under Penal Code Section 1203.4. Here is a Guide: http://www.avvo.com/legal-guides/ugc/guide-to-12034-relief-in-california----by-robert-sanger-sanger--swysen
Sit down with a good criminal defense lawyer, even if it is just for a consultation (many lawyers will do that for free) and let the lawyer know what you want to accomplish. It is often possible to find a way to help if we know all the facts and you have a worthy goal like trying to go to school! Good luck!
This is not legal advice. In order to get legal advice, you need to retain a lawyer and establish an attorney client relationship. So, talk to your lawyer! [I am licensed to practice law in the state of California and am admitted to the federal courts in California, Washington D.C., the Ninth Circuit, the U.S. Supreme Court and a number of other federal Circuit and District courts. For legal advice, you need to retain a lawyer in the jurisdiction in which the matter is pending.]