Suggestion needed on Notice period conflict!

Hi,

I am working in an IT company for the past 2.5 yrs. I have got a better opportunity in other company and hence I need to leave the present company. My new company wants me to join within 2 months, but my present company is not ready to leave me without serving 3 months' notice period. They are not ready to give me relieving documents if I don't do so.

I checked my appointment letter which states:
1) After commitment period, prior notice of three month working days must be given to leave the company.
2) Company may terminate the appointment by giving one month notice or payment of salary in lieu thereof.

I am willing to serve 1 month's notice period and ready to pay 2 month notice period, but my appointment letter does not mention anything about buying notice period, neither my company is allowing me to do that.

Can something be done in this case?
1) Are the clauses given in my appointment letter legal which asks for 3 months notice from employee but will give 1 month notice to employee?
2) is it legal from a company's part to terminate employment by paying 1 months salary but not allowing employee to pay for notice?