Tracking a user from another site - Google Analytics

My client pays for a link on a directory. The client wants to gauge the ROI from having this link (it costs a lot, but I can see the directory is the biggest referrer).
How can I track to see what path a user follows once they click on that link? I need to see the user’s path through the website, eg:
user clicks on directory link->views relevant product page->adds product to cart->checks out.
Ive setup conversion tracking before (although that seems to have stopped working since I initially tested it - but thats another story!), but Im unsure how to do it to track a user’s flow from a referring website. Ultimately Ild like to assign a conversion value to the goal and possible the name of the person and transaction ID.
At the end of the day, the client wants to know “This directory link has cost me $100 and has made me $??? in return”.
Hope that makes sense!

Hmmm, Ive found one way which is to setup an Advanced Segment. Although I dont think this will go into the depth I require. Ive set one up to show how many people from the referral link visited the goal page. Im not sure that gives me the nessacary detailed information. Im interested to hear your comments.

Hi, Ive left my Custom Segment to do its thing for a week or so. Its returning 0, and Im not sure if thats because Ive set the segment up wrong, or because there genuinely hasnt been anyone that has fulfilled the criteria of my segment.
Basically Im wanting to see how many people from a referring site has resulted in them sending the enquiry form. My Segment is setup thus (I have 2 steps in my Segment):
step 1: SOURCE contains ‘’.
step 2: PAGE contains ‘enquiry-form-complete.php’

Now to me that should show all those people coming from which resulted in the enquiry form being sent. Have I set that up right? I can post up a screen shot if that easier.