I think you meant to type "the next week" not "the next day". If the OP is booking a non-home resort 7 months out, they can't book a new 1-night reservation the next day, they would have to wait until they are 7 months out from that night.
The best (but most painful) option is to call MS day by day to add those last two nights one at a time or wait 2 days and call MS just once to add the last two nights at once.
For a low-demand resort or time, waiting a week to make a new two-night reservation for the last 2 nights is definitely an option. But for BWV I wouldn't risk it. Someone else booking 7 months out could get through online booking a little faster and grab the last room before the OP manages to do so.