Few things are necessary in brewing. Raising the temp will generally help the yeast clean up more quickly and completely, though. It will probably improve your beer to do so. How much? I couldn't say, as it all depends upon the particulars of your fermentation and palate. As long as you can hold the temp steady, at least, I wouldn't worry too much. Keep that brewbelt going, and see if you can't move it to a warmer room (5-10F warmer) for a few days.