I'm assuming we can also sell the items we don't need (thundering short sword, +1 longbow--both small size, rapier +2, 5 +1 elfbane arrows, cloak of charisma +2, horn of fog). That would yield 12,920 gp, bringing our total available to 21,836, leaving us each around 3,600 gp to spend.
I am willing to contribute most of mine to boosting Pender's greatsword in some way. I would like to buy a few more scrolls, just to be prepared, but I'll commit 2,500 toward Pender's sword.