oreopoulos,
The easiest way for you to go is to get a consultant to send you a DWG with their Styles pre defined in the DWG file.
Then under your save options, you will see on the right hand side, "Template for additional settings" this is where you browse to your consultants DWG file and choose it.
Then under "Font conv" you choose all of the ArchiCAD fonts that you have used then in the AutoCAD part of the dialog you write the style that you want to convert to.
E.g Arial----->(oreopoulos)(Which is the style name in AutoCAD)
HTH.
Cheers.
Ben