I generally dive the Caribbean but have an ice capable Apex regulator. I don’t know about your regulator but check with the mfg and then also, and more importantly, your Michigan dive shop. I would think that your current regulator would be fine for the "normal" Michigan dive season but for an ice dive, make sure it is checked and serviced for this dive type as some lubricants used may not be appropriate for the temps that you would encounter.
http://www.wunderground.com/cgi-bin/findweather/getForecast?query=gaylord%20michigan&wuSelect=WEATHER
Check this site for weather conditions including surface water temp (select "Marine"). Currently the surface temp in the lakes looks to be around 65 F. NOAA may have some at depth data ...