Need help fixing a costume

[lucasrobin]

Hello,
I'm working on creating a SMW-style Waluigi, but the spritesheet only has two frames for walking (not counting the standing frame), and I need three walking sprites. The sprite I'm using is about 2 to 4 pixels taller, which makes it not fit well. I'm aiming to turn it into a Ninjabomberman costume.

I also want Waluigi's swimming sprites to be used when he floats, but I don’t want them to share the same sprite as the falling animation. Do I need to edit the .ini files for this? How do I go about making these changes?