i know this is on the forum somewhere, but i would like to know what is the latest myself and my wife file for my removal of conditions...

my card expires on the 26th may this year

A few days before the green-card expires. It is recommended to do it sooner than that in case something complicated happens like petition lost in the mail, check bounced...

I'm uncomfortable with how close I cut it to my expiration date. If I were you and you want to file it at the last possible minute, I would definately be sending it overnight at a week prior to to make sure you don't hit any unsuspected road blocks.

You can apply right up to the day the conditional GC expires. Once you send in the I-751 application, it takes about a month to get the NOA that extends your Permanent Resident status for a year, giving employment and travel authorization.

So, if you require proof of legal residency before the NOA arrives, you will have a problem.