Hi Ky,
Check out
http://reedreviews.net/ and scroll down and you will see some European/Autralian reed makers listed. Some may ship out to your area.
Plastic reeds for oboe have not reached a point where they are usable. They would be a terrible waste of money. (Clarinet does have some good plastic reed options, but not oboe)
It is normal for your right thumb to hurt until you get used to the weight of the oboe. There are supports in the form of neck straps and FHREDs if you find that you just can't get used to the weight of the oboe (This is the FHRED -
http://www.quodlibet.com/FhredGen.htm ).
Your low range problems could be the oboe, the reed, or you. My first blame would be the reed
, but you really need to have another oboist around to help.
Hope you have luck finding a teacher. You can try other oboe boards at IDRS.org and woodwind.org to see if you can get better feedback.