i know you're expecting expert advice and you will get it soon from the people here at the brickboard, but right now i am probably the only one who happens to have read your message, so please bear with my less-than-expert advice (i am a novice, not a mechanic at all)
anyway...
sounds like the universal joint (u-joint) has broken and if there are parts of your car disconnected that's not good. i looked at a diagram and it seems the part that has disconnected is where the drive shaft is. if that's the case, i believe the drive shaft "tells" the wheels to turn and if your back wheels aren't getting this message then your front wheels are having to pull the whole car, which might be why it's struggling in the first gears.
again, i don't know much, and i am not in the Mass area so i can't help you with a mechanic, but be pacient and i assure you someone with knowledge will help you soon.
good luck,
trina