If you look on your page you will see there is a "Text Box" you can do things in. One of the things you can do is drop in code for a small representation in there of a Google calender. Of course you need to create a Google calendar for your group in the first place.
I know more, not much, about this, but I have no time for several days to do more. Poke around Google Calendar and llok at calendar widgets or gadgets and I bet you can figure it out.
I just started playing with this site today and I wanted to do the same thing. Since we are a meetup group, we have a calendar in another format but I couldn't get it to come in. I used Feedburner to pull in headlines of upcoming events. It worked out well. If there's an RSS feed of your events somewhere, this would work for you too.