The VSS is a sensor which is more or less directly linked with your auto shift patterns.
The speedo cable comes from the gearbox, then into your speedo gauge.
There is an electrical swith within this sensor that opens and closes at a frequency goverened by how fast your speedo cable is rotating.

Your Ecu uses the information from all of your load sensors along with the speed signal created by the VSS to determine what gear it should be in.
I have put this very simple so that you could understand.

In all honesty, your vehicle speed sensor could have eventually worked out of phase and caused this problem, but with the crunching and slipping and grinding, replacing the speed sensor or even carrying out the speed sensor campaign will not rectify your problem.

Have the gearbox overhauled or replaced then have your codes cleared and then re-check them again a few weeks afterwards.

*update*
I still dont have the money to get it fixed yet, but I took it for a drive today to keep the fluids flowing. It did much better then lasttime. How often is it good to drive it? or is it bad to drive it?

If things are grinding and crunching inside your transmission, then it is probably not a good idea to drive it at all.

Have you had your codes checked yet???

my CEL only came once whne I first bought it. Then it turned off. So I didnt get it checked. I have tthought about it. But for some reason the battery keeps dieing and most of the time have to get it jumped to start it. It doesent die complealty because the dome lights still work. Would that reset the code. Should I go get it checked? Theres a place to get it checked about 2 miles from my house so its close. Thanks
Jessica

Yes get your codes checked, and no your flat battery will not erase the code, but you may also get another code in your system that maybe something like, Voltage system low or Charging system low voltage.
Don't let them sting you for anything unless they are 100% sure they know what the problem is.

You just want to get codes mainly for your Auto transmission, so that we can determine where your problem started and what else it has taken out with it.