Dorjes are cheaper "per charge" than power stones.
You might be able to combine UPD and
these rules to use a power stone to access powers outside of your list. If the DM doesn't use the CPsi nerf, you can even use your own power points to manifest these to avoid flushing (using up) the stone.
A somewhat less controversial way would be to take leadership, and get a psiwarrior (or other) cohort that has the powers you want, then use
Thieving Mindlink to use them.
Slightly more cheesy method: get a cohort with Expanded Knowledge, and use Feat Leech to "borrow" this feat. Since you're borrowing the feat,
and not the power it is applied to, you're not necessarily bound to choose the same power to apply it to as the person you stole it from. So this lets you use any power at least 1 less than your max power level. Of course, the DM might not like/allow this.
Metaconcert is another potential way to use followers/cohorts to gain powers known.