Looked up that radio on the net and have never seen it before...and it does appear fairly basic so maybe doesnt support expo. but it may have some sort of endpoint control.
Have a trawl through the manual...what your looking to do if possible is decrease the movement of the swashplate over the range of the stick (and maybe the tail). This may be through endpoints/ATV's for those particular channels.
This will help prevent the model from "running away from you" and you will be in control (hopefully!!!)
Marty.