How to point Itunes to a new location where music is stored Cannot locate music now it is on an external drive PLEASE HELP!!!!

Question

Background Info
i have recently got rid of my Windows machine an am now using my MacBook as my main machine  
On the old windows Desktop   i had my music set up as follows  
Itunes libary information:
C:\Documents and settings\Lee Robinson\My Documents\My Music\
all of the Music files were stored on the PC as follows  
G:\Music\My Music
Before i got rid of the machine i backed up all of my music and my iTunes libary files as follows to a External USB Harddrive that is now connected to my mac
Music Located @
/Volumes/AFRO-PORT/My Music
the iTunes Libary is located at the following  
/Volumes/AFRO-PORT/My Music/iTunes
what i then did was to copy  my itunes libary files at  /Volumes/AFRO-PORT/My Music/iTunes  to my local Mac machine .....
/Users/Afroboy/Music
Problem
Now when i fire up Itunes, i have all my playlists, ratings abum art etc...... but the problem i have is that itunes cannot locate any of the files. I guess that this is because my entire libary is still pointing to
G:\Music\My Music -  as on my old windows PC
How do i tell itunes that this is no longer where i keep my music and for the actual MP3 files itself it needs to look at the following path
/Volumes/AFRO-PORT/My Music
... all file structures within these 2 file directories remain the same  
I would really appreciate the heklp-  my music collection is quite big and i dont want to loose any of the work i have done building it up over the past 5 years  
Cheers
LR

Answer 1

Hi  - thanks for the response  
yes thats right, i have always kept my itunes folder and the directory containing all of my actual media seperate  
all of the Music files were stored on the PC as follows:  
G:\Music\My Music
Itunes libary information:
C:\Documents and settings\Lee Robinson\My Documents\My Music\
Your quite right, doing the above method that i have, turns it really messy when you  when you try to move your entire collection. i saw this article earlier today 
iTunes: How to move your music to a new computer - http://support.apple.com/kb/HT4527
..........wish i followed it before hand  
The only Semi work arond i have found is to go to File> Add libary.... and brows to what is now my new external drive with all my music on  /Volumes/AFRO-PORT/My Music/ .
Once the import was complete it effectivly dupicated my entire libary -  So i then went to
File > Display Duplicates to show duplicate items, sorted by date and removed all the duplicate items  
.... So far seems to have worked ok however i have lost my play lists, their all on my iPod anyway so all seems fine now  
As you said iTunes wants you to do thinngs in a certian way and it certianly makes you pay if you dont. So now my question is, so i dont have this problem in the future..... do i
A) Manually move all of my Music files to my iTunes Liabry and have everything in one folder (If i move manually where do i need to copy all my files to?)
B) Start from Scratch and let iTunes do it, so i have everything on the external disk