^Will a single Type-R take 1200W+ on it's own?
Anyway, amp upgrading still sounds like a good idea.
If you wanted different subs, perhaps two Kicker CompVX instead of the Type-Rs? Maybe a nearly sideways move though. But otherwise you're spending more money and then you're going to need more amplification anyway, lol.
There's also the Type-X, but I doubt you'd be able to keep it under $450 including shipping. And again then you're probably going to be underpowered...