You really seem like a smart and honest guy with good English skills Are you sure this is the best you can do? I really hate for you to struggle for three years. Friend of mine is American and working in education (making 10 times what you are offered plus housing, etc.) and she hasn't been home in two and a half years, although that's illegal, Every time she's up for vacation there comes a new excuse. If this job will help you in the future you may want to go ahead and bite the bullet. But do know you are being taken advantage of and I think that's unfair. And I know it won't get better once your boots are on the ground here.
Mandi