Eric,
Welcome to the Best place to be on the internet!
I am sure you will like it here.
As far as a replacement air box, well I would just go a head and let the mechanic fix the one you have.
I think an approved replacement is quite a bit of $$$.
Notice the one that Graeme linked to at Spruce has a notice at the bottom of the page:
For Cont. 0-200 engine as used on Cessna 150. Also fits Cessna 120, 140, and PA-22 Tripacer. Order filter, gaskets, studs & pins separately.
Not FAA/PMA Approved.