If you are ready to sign the agreement you may go ahead, other wise you have every right to reject the offer and get out of the company.
No. they can not claim back the stipend paid to you during your training period.
Need not get frustrated, apply to other companies. If you do not want to continue their you can always leave. But once you sign the agreement you are bound by that. So think very well before signing.
And personal advice is, 3 years is not a small amount of time and you will not know about the future market trends and opportunities. If it would have been for one year or so you could have given a lot, but 3 years is not advisable.
So there is nothing to worry about so that you feel frustrated......
All the best for your future career.......
9th May 2012 From India , Bangalore