Could I File I-90(Green Card Renewal) Form At U.S. Embassy ?

Hi does anyone know if a green card holder can file the I-90 (green card renewal ) form at a U.S. embassy ?
I am currently in London and need to file for renewal as my green card expires in less than 6 months.I know i do not lose my status as a permanant resident but the thing is i will not be back in the States in time to renew the card.
I do know that if one is outside the States for longer than the one year one would need to apply for the re-entry permit , which i posses (just in case ).
In case you are wondering, yes i did call the U.S. Embassy here in london but they have a recording that asks you to call another number ( a very expensive 09 number ) which will cost £1.45 per minute..so if they leave me hangin on the phone, that will cost me a small fortune in bills.

So if anyone has concrete info about this i would be gratefull.
Cheers
Sost

Green cards are not renewed or extended outside the US. If your GC expires prior to your trip to the US then use the re-entry permit to seek admission at a port of entry. You may also apply for an S1B immigrant (returning resident) visa at a cost of 400 US.