Any good detail shop should have an extractor (much like your home
carpet cleaner uses), this should be able to remove most of the coffee
that is near the surface of the foam that is staining your seats.  The
service should not cost that much for such a small area if they are
willing to do it.  Another DIY option is to do it yourself.  I used to
use water/woolite (6:1) for most of my interior cleanup jobs.  Spray the
area liberally and allow to soak in, agitating with a soft upholstery
brush.  This will 'loosen' the stain in your foam.  Then you can hit it
with a standard shop-vac to suck out the cleaning solution, coffee, and
hopefully your problems.  As a side note though, I would not try to do
this with less than 3-4 horsepower on the shopvac.  The best solution
though is to go to a good detailing shop and have them extract the
stain.  Their machines have far greater suction capability than all but
the most industrial Shop-Vacs and they are purpose built.

-Nate
'84 Westy
Small-time detailer in a previous life