Once frost arrives, will it stay that cold? Here, it seems like we always have killing frost then things warm up for a while. If same is true for you, by covering and protecting from this first frost, you may be able to eek another week or two out of them... But you would have to protect the ENTIRE vine, not just the fruits.
Also, if you can put up a plastic tunnel over the plants -- or even just a wind shelter -- they will be warmer and may ripen faster.