My parents got divorced over some canadian gold digging bimbo too. I know how it feels. She's married already, but they're just "friends" (bullshit) As soon as he passes anything left in his will to me or anyone else will be stolen by her. Fucking hate her!
Try messing with her makeup. Maybe rub small amount of bengay or icy hot in it. Mix glue with her nail polish. Water down her nail polish remover. Put food coloring in with her shampoo or soap. Put some icy hot or bengay on/in her soap. Put a thumbtack in her shoe or somewhere she normally sits. Hide her car keys or turn off her cell phone and hide it. Spit in her food, over heat it, undercook it. Get off in her bed/on her side of the bed, get it on with someone in her bed/on her side of the bed. If she has any toys use them anally and don't wash them just make sure they look clean. Then when she uses them she gets a yeast infection or bladder infection. Butter her bathroom floor. Leave the seat up. Mess with the length of her bra straps. Tell he she looks likes she's putting on weight.
Make her feel like she is not wanted. Change the atmosphere of the room she's in. Make her want to leave.
If all else fails, talk to your dad. He should love you more than her. Tell him she needs to go and that you're serious about it. You may take flak, but if you get your true feelings out there and he knows it could sway him. Tell him that you should be the most important girl in his life.
I really hope you succeed in bringing that gold digging bitch down. Good luck I hope I have helped in some way.