Good for you for wanting to use condoms and a backup hormonal method!
If you're not comfortable getting the pill from your own doctor, you can try Planned Parenthood (1-800-230-PLAN) (in the US). Using their site, or calling that number, you can locate an office in your area. Also, try the Yellow Pages in your area, there should be several centers listed.
As far as how long it takes for the pill to be effective...the general concensus is that it takes at least one full cycle before you can consider yourself protected (some pills will say two weeks, however it's generally best to wait an entire cycle just to be sure). But remember that is assuming you took the pills properly and on time, didn't experience an illness which caused vomiting or diareah, or took a medication which would have interferred with the pill (all of which can make entire cycles of the pill be less effective than they should be). Talk to your doctor about which hormonal methods or pill formulations will be best for you.
Scarleteen Advocate (and Labia Lady)
"The whole world is full of morons...they just congregate on the internet cause it's easy for them to push the buttons."