I'm afraid, the answer is no.
Re-entry permit is only available for a period of your valid stay in the country. The date is specified in your most recent stamp.
Yes, you are eligible for preliminary extension of your stay if you have a good reason. Traveling abroad is a good reason (just show your air ticket), but in general, this can also be a long travel within the country.
However, in order to get an extension, you need to get papers from your school, proving that you are still attending the classes — just likewise you do every time when you extend your stay.
Caveat. With current Thai regulations, there are two ways to extend your stay:
- "Normal" extension, in two steps: (1) You pay 1900 THB, get 15 days, during which the Immigration officers may come to your school and check if you really attend the classes. (2) Then, you come to the Immigration office and get another 75 days;
- "Special" extension: 90 days at once, 3900 THB.
Obviously, you need the 2nd way since you won't be there.
- Run to your school and kindly ask them for the necessary paperwork; I can't guarantee they will be able to do it within two days, but give it a try;
- Go to the Immigration office and:
- Extend your stay; if asked for the reason (of preliminary extension), show up your air tickets and say you also plan to ask for the re-entry permit;
- Get a re-entry permit;