1. Go to crucial.com to buy the right amount of the right RAM for your laptop.
2. Open the case
3. Put the new memory in (if necessary, first remove the old to make place)
4. Test if it works
5. Close the case.

The touchpad problem is quite something else. Most likely it's either a setting, a driver issue or a mechanical issue. Impossible to tell from a distance. Did you check your settings? Is the program that handles the touchpad running (with my Dell here, it's called Apoint,.exe, but most likely it's different with you)?