Resignation during probation period

Dear all,

pls guide me i am in critical situation.my employer offered me a storekeeper job but the visa is light driver .
.i have signed a contract with six month probation period. beyond the contract they asked ME to sign in a paper for visa expenses of 500BD.i was worked 25days as a storekeeper now they shifted me in to another department which i am not interested. now i want to resign my job and officially i have given letter to my boss .also sent a email copy with cc to HR manager.
what i supposed to do? will they ask for visa charges ? do they release me with in one month? also i am trying to find new job. if i got a job what i should do further? i am new in Bahrain.
your valuable advise are welcome.