Net Express to .Net Conversion ?

We are running a ten years old desktop based application. Presentation layer or GUI is built on Net Express deployed on Windows machines and business logic (or transaction program) is built on Micro Focus Cobol deployed on UNIX server. Cobol programs use embedded SQL to persist data on Oracle database. We are now evaluating different options to switch the application to a web based application. Organization has taken strategic decision to use .NET framework for any future development though J2EE option is still open if it has significant edge over .NET. Cost and quick turn around is key factor while evaluating different options. We have following options in consideration.

1. Replace Net Express front end by .NET and re-use micro foucs cobol transaction program and embeded SQL.

2. Decommission existing application and re-write a brand new application on .NET framework.

#1 option sounds best choice as it involves less development and less QA time. But IT team does not have any prior experience on this kind of conversion. So I am seeking expert comment on following 

1. Is it a feasible solution to replace Net Express with .NET and re-use MF cobol deployed on UNIX ?

2. I feel Micro Focus Visual Cobol is capable of doing this but now sure if it will work in our existing architecture where transaction programs are deployed on UNIX.

3. Is there any online guide / document which can help us on this conversion?