First off you should be able to take Wisps in singles. That would jump your
plat funds way up pretty quickly and still offer xps as well. If you want a
good place to hunt run on over to Misty Thicket. I found it a pretty nice
hunting spot around that level. You could solo there for quite some time.
When you max out there take off for Oasis and that can carry you even higher.
The loot in both places is not very good so do not expect to get rich. If I
were starting over that is probably what I would do at least.