Decent tanks are getting scarce and I'm guessing shipping to you would be very expensive unless you found one in country.
Even a really nasty tank can be used if cleaned and coated. Take the pump and cap off, tape the cap opening and add a few cups of nuts and bolts with some water and detergent to the tank and tape off the fuel pump port. Shake and repeat as needed to remove the heavy scale.
I've heard vinegar or Coca-Cola to treat the lighter rust, do some searching.
Flush with water and dry then use a tank sealant like Por-15.
One caution is that I believe there are two steel tubes inside the tank for vent and overflow drain that you want to try not to damage. The overflow is not critical but the vent tube needs to be open to the top.