As an interim solution before you get a hold of plexi glass, have you tried putting a large towel over the gate? It might be able to prevent climbing because there's nothing for their little feet to grip onto?
My little Casie is the nightmare child - she was shredding the potty pad on a daily basis. I also tried the plastic trays that hold down the pad, but she'd get so determined, she started digging holes in the middle of the pad. Applying bitter apple around the edge worked for us.
Hang in there!! You can do this! The first year is definitely the hardest. We've all been there. It's like a roller coaster - they're so cute and you gotta love them, but when they're being bad it can be so very frustrating!
