Ching, I guess an AV Amp. 5009 can't drive PM1 good as well, if any one of us wanna upgrade a 2 ch. system, a stero Amp. is needed, perhaps, you may buy a int. Amp first, you'll see the true power of 705, I am also a user of B&W 705, they are good speakers, and welcome for any power from Amp., the better Amp. to drive, the better sound they perform, it will never be late to upgrade the Amp. first, cause you've a pair of speakers already.
In the other hand, if you want the speakers to be AV front, PM1 may not a good choice, CM7 is more suitable.