Swapping the pumpkin is the way to go since you have limited skills. You can price them online new, or buy a good used 3.23 Sure Grip (spins BOTH tires) for around $400-600. You'll want one with the larger yoke to match up to your existing driveshaft, and best to have a pumpkin casing with the casting # ending in "742" or "489". It's a 1-hour job for an experienced mechanic, so you could always have a shop install it at reasonable cost.
It's not that complicated to do yourself if you want to give it a go. Some basic tools, a few gaskets, and some silicon sealer. I'm sure there are a multitude of Youtube videos that walk through the subject.
Edit: I see you are in the Netherlands, so an entire pumpkin may be cost prohibitive. In that case, consider buying some new 3.23 gears that fit your existing pumpkin and have a mechanic do the work. Try these guys for info:
RANDYS Worldwide | One Stop Differential & Drivetrain Shop