what's the budget?
cinderblock in the basement would be cheap enough, then it's either use a liner or use the glass from your 180 and do a build out, as long as ypu keep the glass ontop it wouldn't be a pressure issue. (ie say your new build will be 40" high, as long as you set the glass on the 2nd row of cinder blocks it will be in the same 2' depth as it is now)
then you'd need a sealant like pond armor, hydroband, or one of the cheaper sealants.
do another cinderblock setup for a sump this time without windows and use the same selant and then all you need is plumbing.
cheap way to go too as cinderblocks are just over 1$ a piece mortar is cheap, and the sealant shoud be reaosnable at 100-160$ for the amount you need.