Tooth infection in redone filling. swelling and pain gone from amoxcilin. how long will this last till i have to get an extraction. no healthcare atm.?

A few days: You need to see a dentist for treatment. The antibiotic only suppresses the infection. The infected tooth is like an infected splinter, the source of the infection has to be removed. In the case of the tooth you will probably need root canal treatment or an extraction. Don't delay, infections in this area can spread to the brain and become life threatening.

No way to know: Have you discussed with your dentist alternatives to extraction or is extraction your only option? Amoxicillin will only help to keep the infection and therefore the pain under control. Even if you stay on the antibiotics there is no way to know when the infection(and pain) will rebound. If you need an extraction, the sooner you have the tooth removed the better.