shifting shuts my car off

So i am new to this 75 dart and i want to drive it daily.

As of now i still have to spend about 5 minutes warming it up to get it to run without shuttin off, and i guess i can deal with that at least for now,

however when i shift into reverse it dies right away. it does the same going into drive, but i rarely reach that point because it dies going into reverse.

if anyone can give me some idea of what might be causing this that would be great. also if you have any idea why it may need so much pedeling just to get warmed up, that would be cool too.

thanks a bunch in advance