Have you not been in contact with them yet? And they haven't contacted you? That said, generally speaking, it would be to your advantage to let them terminate you, not the other way around.
Looks like you would be eligible for the subsidy if you are terminated because your FMLA has been exhausted and the employer won't hold the job any longer.
http://www.irs.gov/pub/irs-drop/n-09-27.pdfQ-4. Does involuntary termination include an employer’s action to end an individual’s employment while the individual is absent from work due to illness or disability?
A-4. Yes. Involuntary termination occurs when the employer takes action to
end the individual’s employment status (but mere absence from work due to illness or disability before the employer has taken action to end the individual’s employment status is not an involuntary termination).

