"Columbia" Teapot and serving dish

This is a teapot and matching serving dish that I purchased at an estate auction approx 2 years ago. I think it is porcelain or pottery, but I really don't know anything about it, I just bought it because it was pretty and looks very old.

The stamp on the bottom says "Columbia" Ye Olde Hall Potterie Staffordshire, England. I have posted a pic of the stamp, but the date is not very clear, it says: Este 1790.

The set is green and gold. The green looks to be printed under the glaze and the gold is on top of the glaze. It is in excellent shape, no chips, but it looks like it was used b/c the gold is worn off of the handles of the teapot and lid.

I can't find anything online. I would love to know how old it is and what it might be worth.

I'm a history buff and would appreciate any info you have about the piece or the potter.

Thanks!

P.S. Will post more pics if you tell me what to focus on!