Recommend an $150 or less Co2 rifle

I have the Diana Chaser in .22 caliber. A friend of mine tuned it for me. First of all clean the barrel. It was full of packing grease. My friend re-worked and crowned the barrel. He also did several other improvements. All of which can be found on u tube. The rifle shoots the Crrosman premier 14.3 gr pellets at 11.4 ft lbs, 604 fps. A1/2 inch at 25 yds. This little rifle is a lot of fun for me and my grandson. The squirrels and rats don't like it much.
 
When the Crossman custom shop was open I ordered a small light weight rifle with a walther barrel, camo stock, match trigger. It's CO2. I thit was based on the 2240. 

Stupid accurate at 20yrds. But doesn't have the power to kill anything but a bird at 7fpe. It was for my 7 year old. my other ex-Co2 was a Hammereli 850. Walther barrel again. I got it for my wife. She out shoots everyone with it to the point you get pissed off and just quit. I converted to a large CO2 tank and it would go 400 rounds till low. But only 13FPE. 

I converted it to HPA and set the reg at 1800psi, 2 stage trigger mod, hammer spring, and polished slide hammer. 26.5fpe now. Not a fan of C02 anymore. Would rather have HPA.