This is all I could find -- looks like your options are extraordinarily limited:
On Tuesdays and Thursdays
Leaving Hautvillers (stop in front of the Tourist Office) 1.55pm
Arriving at Epernay's station 2.05pm
Leaving Epernay's station 4.10pm
Arriving Hautvillers 4.20pm
I found it here: http://www.hautvillers.fr/default_en.asp
There is no regular bus service.
If you are from Epernay, how come you don't already know this.
If you are not from Epernay, could you please amend your profile to show which country you come from. The advice given sometimes depends on this information.
There are very few public bus services outside the towns in Champagne. You'll be better getting a taxi from Epernay station, and then asking him to come back and pick you up. If you're in the region for more than a day, then you might be better hiring a car to get out and see the region.
Hope this helps you :-)
Thankyou pepperhall - this is what we will do! Judy302