Murph would have been the best person to address this but he doesn't post very often these days....
I have used the GIS functionality on occasion in C3D although I'm sure I have only scratched the surface of what it can do.
Unfortunately C3D and Map work on different types of data and the two can't "talk" directly to each other e.g. look at this post http://forums.autodesk.com/t5/AutoCAD-Map-3D/Bring
I often use Map to bring in GIS datasets from the UK OS opendata website i.e. DTM data, contours, vector info etc and this works well and can be exported to plain CAD.
Take a look at this link too http://docs.autodesk.com/MAP/2010/ENU/AutoCAD%20Ma
It's possible that Civil 3D, through having Map 3D incorporated, can link to your GIS data and even edit it. You can definitely import and export many types of GIS data. Ask your GIS person what kind of data you have, what kind of data he would like from you and if the data is kept on a server where you might access it. Once that is known we can start to point you in the right direction.
Being involved in Surveying. I have to add this. The biggest difference between GIS data and Surveying or Civil Engineering data is the accuracies that the data is collected at. Be sure you know how accurate the data is before you use in in any design. Surveyors like to say that GIS stands for Get It Surveyed.
The gap between GIS and Survey is closing. I just got Lidar of our whole County with 2 meter spacing and 15 centimeters accuracy at 95% from out Planning Dept. That's a lot of data! But we will still have to have our Surveyors do topo for our projects. But this will be amazing for preliminary planning and to fill in the gaps around the outside of the surveyed area.
Let us know what you find out.
Just found [this] link. It's for 2012 but should help. You should have the equivalent in your help files.
I'd highly recommend doing searches on "FDO" and the keyin "mapconnect" to see what you can do with GIS. Mapconnect is a Map3D tool available in C3D. FDO made a pretty big debut in C3D 2011 with subscription packs (?) but apparently got better in later versions.