Bridge or AP Mode on R7900P

> [...] I would like to now add the R7900P router into the network as a
> bridge or access point to increase the range of the network. [...]

   "range" to _what_?  A bridge and a wireless access point do different
things.

   Visit http://netgear.com/support , put in your model number, and look
for Documentation.  Get the User Manual (at least).  Read.  Look for
"Set up the router as a WiFi access point" and "Set up the router in
bridge mode".

   Which one do you want? Is there some actual problem which you are
trying to solve?

> [...] each time I go through the process to set it up it does not work
> as expected. [...]

   Think, for a moment, about how little useful information that
non-description conveys to the non-psychics in your audience.

   "the process"?  What, exactly, did you do?

   "does not work as expected"?  What, exactly, happened?  What,
exactly, did you expect?

   "does not" is not a useful problem description.  It does not say what
you did.  It does not say what happened when you did it.  As usual,
showing actual actions (commands) with their actual results (error
messages, LED indicators, ...) can be more helpful than vague
descriptions or interpretations.

> [...] My assumption is that this is not possible to setup on a mixed
> network, [...]

   "this"?  What/which?