How do I re-map individual keyboard keys?

1) I'd like to remap the pointless key below the Escape key (±/§) to be an enter key.

2) I'd like to remap the regular return key to be an enter key.

I do tasks that require a proper enter key and using the cursor instead of the keyboard is starting to get on my nerves now! FN-return doesn't work - I think that might be for different models to mine. I also mainly use my left hand when typing so using the return key on the right side of the keyboard is a pain anyway - having a proper enter key on both sides of the keyboard would be ideal.

Is it possible to just remap the two individual keys in question to do what I want them to do? Thanks in advance.