What you could do it make two reservations, one with points and one with cash (probably the weekend nights) and if you're lucky, get them linked so you don't have to move.
You get what you booked on points. If you want the one bedroom, you need to book that on points or pay cash for each night you need. You can't mix points and cash for a single night.
If you are going before June 27, the buy 4 get 3 free nights promo may make booking all cash for a 1 BR a very attrctive deal. You can then bank your points and stay in a 1Br on points next trip! -- Suzanne