First thing is have the tranny completly flushed with a power flusher not just a fluid change. Call transmission service shops and ask where to get it done. Then change the filter.

If it has not significantly improved to satisfactory, have the operating pressures checked and adjusted. The previous owner might have had it adjusted to give very soft shifts (low oil pressure). This causes lots more clutch wear.

If operating pressures are OK, what you have left are worn clutch linings on the front clutch.

It only costs around $125 for a transmission rebuilder to rework just the front clutch, but removal/reinstall labor can add $500 to that.