Any mechanics/mechanically inclined people?

So instead of paying the $350 a garage was going to charge me for replacing my brake pads & rotors on my '03 Mercury Sable I decided to use the knowledge of cars my dad taught me & DIY it for $118. Here's the issue I'm having: we just got this car for hella cheap & there's SOOO much rust. The bolts to the caliper were basically rust welded on (my boyfriend legit BENT his ratchet trying to get one bolt off), spent a good hour & a half taking off the caliper itself but now the damn rotor won't come off!! It's stuck. Any tips on how to get the rotor off?? We've tried whacking the crap out of it with a heavy hammer.

This pic was taken before we took off the caliper (obviously). Just to show how much damn rust is on this.