Roadiechick, here's what I do...

I race on Saturday, so keeping that in mind.
Sunday is about 110km with the bunch - easy though, only averaging about 30-32kph.
Monday is rest day.
Tuesday is 40km with lots of sprint work in it.
Wednesday is an 80km ride that has a 3km hill climb in the middle of it.
Thursday is a hard 70km ride.
Friday is about 20-30km, very easy.
Saturday is racing - about 60km at the moment, plus often 10km each way to and from racing (good for warm up and cool down).

As for whether its time for you to up the kms, well, how do you feel during your 250km week? Do you find it easy or difficult to do that much? On bunch rides are you able to do your turns comfortably? If this stuff is easy for you, then you can probably increase your kms. Do it gradually though, maybe just to 300km. Maybe there is a longer ride that you can do on the weekend or something.

Your other alternative is increasing the intensity of your training. Maybe you can try changing one or two of your rides to faster bunch rides in your area.

Also do you race? What sort of distance and speed?