I'd offer to help, but I'm short of spare time right now.
Allow me to make a suggestion. Get a notation software. "Anvil" is a freeware version. "Notation Composer," and "Finale" are there if you can afford them.
Then you can pick out your melody line, note by note, play it in real time, and change it, until you are satisfied.
I end up doing about 1/3 of my songs that way. It's not easy for me, but I'm almost certain that you'd have to be a more competent pianist than I am, so picking it out as you input it into the software might be easier for you.