Network Audit Questions

I have been tasked with performing a detailed Network Audit for a company.  Within this audit I need to be able to identify and recommend technologies, upgrades, etc. since they have been experiencing lots of growth and would like to plan accordingly.

My questions are:

1.  Are there any software's out there to assist in this?
2.  Are there any templates out there to follow?

Basically, I have never created and presented anything formal like this before.....  I need a blue print!!

Any and all help is appreciated.