Resignation during probation period need Suggestions?

Hello everyone,
I like posting my query on this forum. As folks here suggest best explanations. Query, of mine is that i am an HR in a small organization there are only 5 people so we are not issuing any payslips for the employee and we are issuing only appointment letter. Currently, we are working with 5 employee's but soon i will plan to enlarge it as if my work proceeds. However, our work was going pretty well for some months but everyone is now stepping ahead to better enhance their future so by somehow, Employee in my organization who joined on 1st june 2012. She is very pretty and the only girl in our office but the problem is that she is currently in the probationary period of six month and she have applied for a resignation on 12th October 2012. MD accepted the resignation and asked her to complete all the work immediately now she serving her notices period only for 18days. I don't want her to go but the problem is that everyone have their own preference and their own taste so what can we do about that.

As per the appointment letter these are the terms & conditions for the employee.

1. Bond for one year and probation for six months.

2. In they have leave the service during the bond period they have to pay a two months salary in lieu of the signed bond.

3. Notice period for 30 days.

Resignation has been accepted now she is asking for a relieving letter & payslips immediately.

We have to collect the two month salary for breaking the bond. What should i do please suggest.