Wow, qwerty, you've been through a lot. I feel the not having health insurance and barely scraping by. Not only have you just graduated from college and are looking for work, which is really difficult, you're far away from your family, and you've got a traumatic event in your recent past.
Sexual assaults of any kind are extremely difficult, and they take a long, long time to heal. The best way to get through it is with support. Fredo is right; RAINN is a great place to get started. You might also look in your phone book for a page with a title something like "Human Services Guide." This lists lots of services available in your community, from housing to health care to schools. If you are able to find a local crisis center, they may be able to refer you to a local health center that offers free services.
For the STI exam, Planned Parenthood is always a great resource. You might also try calling your county health department to see if they do free testing and treatment. There is a group of agencies who receive federal family planning money called the Family Planning Councils of America. You can visit their website http://www.fpcai.org/members.html
to see if there is an agency in your state or region. If so, visit that agency's website to see if there are any clinics near you. These federal dollars provide free and reduced cost services to those who can't afford it. You can also search online to see if there is a Federally Qualified Health Center (FQHC), Community Health Center (CHC) or Rural Health Center (RHC) in your area. These health centers provide services on a sliding scale and often provide dental and mental health services in addition to physical health clinics. You should also email your ZIP code to ASHA to find a clinic.
I understand your hesistancy in going to a free clinic, but in most cases, these clinics are staffed with caring people who want to help.
It's great that you're finally facing your fears and are ready to get some help. It takes a LOT of strength to do this, and I wish you the best. Please come back here if you need anything.