^^^ What he said. Gauge pressures will help us diagnose your system. Borrow a set if you need to. Better still, buy a cheap set off of Craigslist or Ebay.
At least it sound like your compressor is running - that eliminates a large part ($$$) of your problem...
On edit: Here is something I found on Craigslist-Baltimore, kinda near you:
http://baltimore.craigslist.org/pts/1881921487.html