I would suggest locking in something at a rate that you could live with, and ensuring that the rate is flexible. Then, as your trip comes closer, continue to look for better deals on both SPG.com and other sites (using the best rate guarantee program, if you can).

I often see some of SPG's properties, including the Four Points, priced really high a few months out, but unless its a massive week in New York (think UN, fashion week etc), the prices often drop. For example, I was looking yesterday and a night at the Four Points Chelsea in February was priced at about $350, but I'm pretty confident that it will come down between now and then. I find the trick is to keep looking...you can often get decent prices (I've paid $129-149 on several occasions for the Sheraton Tribeca, for example).

However, make sure you lock something in early - because New York can be really full on some nights, and you don't want to stay in Jersey!