I have flown R/C a long time and what you are working with right now is from about the late 80's and probably not worth trying to fly. The money you will spend to get that bird in the air can be put to much better use. Trash the whole thing, but a park flyer such as a Commander or AeroBird about $120 to $150 respectively. Then you can go out and actually fly and have a good time.
If you feel the need for full function, 4 channel, buy a Super Star Select or and Avastar Select, join the AMA and find a flying field. Should you not be able to find a flying field and still want full function by the Nexstar Select with the AFS System and a flight simulator is included with the package. Your investment in the first two will be about $490 wheels up and about a $100 more for the Nextar. Great hobby, great people.
Have fun!
FYI-I have owned a toy and hobby shop for over 27 years and my advice would be the same if you were in my store with the aircraft you currently have.