H1B to L1 Conversion, Guidance Required

Hi,

Currenty I am in USA under H4 Visa Valid till May 2015… To get EAD for me, My spouse is willing to change his visa from H1B (Valid till May 2015) to L1.

Please advise whether this conversion is right thing or not. Any advantages or disadvantages involved in this.

What will be the approximate fees for conversion and Do we need to go back to india for stamping?

Thanks,

Priya