Walsue,
You sound a bit like I did a few weeks ago. The decision I came to after reading lots of forum stuff and speaking direct to the schools was to just go for what YOU think is best. If two weeks is all you can spare then fine, the US (especially California) has great weather all year round (fact). So, I believe that in 2 weeks you could get a chunk of your training done. This of course depends on aircraft and instructor availabilty but if you call up the school you wish to attend and explain your situation they will tell you exactly how it is going to work for you.
There is a way that by the end of the two weeks you could get to the point where you are only a few hours and/or exams short of a PPL. This would be if you sat some exams before you went. My instructor advised that I complete Avaiation Law, Meterology and Pilot performace before I go. I also have 5 hours so this to will help.
Basically, don't worry to much, go and get yourself out to the states with an open mind. Rather than think you are going to pass in two, three or even four weeks just believe that you are going to learn as much as possible. You do not have to pay for all your training up front so if you don't fly you don't pay.
I hope this helps you out, I know there is alot to take in and some big decisions to make. Don't believe everything you read on forums, get on the phone as speak first hand to the schools and you will feel much more confident.
All the best with your training.
187.