You have chosen to attend one of the premiere universities in the country, and by your choice, your associated costs of schooling will also come at a premium.
The realities of your situation: as you may already be aware, federally subsidized loans are limited by year level of the student and determined need of the individual; assuming you’ve already filed the FAFSA, in the ‘bigger picture’, you will need to carefully consider the path and length of your college education; sometimes it may take longer than one originally expects; unsubsidized personal student loans (private loans) are costly, and interest is most likely not able to be deferred while you’re in school and capitalizing interest is a slippery slope (that is, deferring interest-only payments until you finish school).
And the possibilities for your situation: If you’re a California resident, you can also apply for CalGrants and Pell Grant, although the certainty of getting these is unknown to me.
Some other suggested avenues for research:
1. Plan your college ‘journey’ based on your total financial picture, and consider that you may at some point need to consider alternatives to full-time status at that school. This might include part-time study, researching prospects for private grants and scholarships, seeking funding by the government for Federal Work Study, working through school, etc.
2. Consider completing any outstanding lower-division coursework from a certified transferable curriculum at a local community college (this requires the advice and guidance of the academic counselors at USC);
3. Status: are you transferring as an upper division student? Are you undergrad, grad, or post-grad? The planning will differ based on your level of study; many transfer as juniors, completing lower division coursework in order to lower the overall cost of education.
4. You can also try talking with guidance counselors at your current school, as they may have additional background and information to support your college planning. Same thing for USC-I’m sure they have a financial aid office that you can correspond with prior to your matriculation.
Good luck with your endeavors, and welcome to Fluther!