How to recover by mnemonic with Etherwall?

I'm trying to transfer eth from the address I've been mining to into coinbase to sell and I've encountered the nightmare scenario I try to send and get back an error "could not decrypt key with given password". The passwords I have written down are not working, for some reason I have two but I cannot remember why, One looks like a normal password with a mix of character cases and types and the second is all upper case letters, might this be something oher than a password? I created this address and wallet like 6 months ago and I'm trying to remember all the details. I also have a 12 phrase mneumonic written down, but I cannot figure out any way at all to put that into the etherwall application. I also do have the json file generated when I made the address and it is definitely the correct one because the address matches but I can't figure out what to do with that either.

I feel like I have enough pieces that I should be able to recover my wallet but I can't figure out how to use them with etherwall, is there some way to gain access otherwise or transfer to a different wallet application? Am I just missing some way etherwall can use these things?

Thanks for any help, trying not to panic but mining has gone really well and I could very much use the money.