Tweak your plan to suit your improved costume-making skills.
Common steampunk fabrics include leather, brocade, wool, cotton.
If you want to go with a fully DIY approach, you can dye things at home using a mordant commonplace kitchen supplies like tea bags and onion skins.
Sewing on a utility belt to a corset is a good idea if your character assumes a mechanical role.
Punk-oriented hairstyles also work great in steampunk costumes for the purpose of contrast.