hmmm, I have the solution to your problem to a degree but after that you would have to research further.
As with marketing offline in multiple magazines, newspapers etc, you should be applying a code to each ad, then you monitor how often a code appears.
Online, that is knowen as passing variables. Ill give you an example. In my backend system I enter the details for each of my ad campaigns, eg, diff signature links, strategic alliances with other sites, google PPC campaign 1, Google PPC campaign 2 etc
And for every different place I advertise my system gives me a different referral ID, so for each diff advertising campaign I use a diff URL eg walkoffwithyourcompetitorsmoney.com?r=1
You can see an example in my signature. Then my system records the new users details, and places the cookie on their PC which will last up to 200 days if they dont revist the site for 200 days my system will issue a new cookie next time they come.
Then when they buy I record the Unique ID of the buyer, and that is matched to the referral ID (?r=1)
This works well because it means that I can see which campaigns refer people, and how much those people spend over their lifetime not just the one visit. I have found that some sites give me good initial traffic, some give me good initial sales, and some provide me customers who return week after week and those are the campaigns that I continue to run.
Every 4 hours my system sends me an email, showing me where I got customers from, how much they spent, how much the add cost me for the four hours since my last report and any PPC costs for the four hours since the last report so I can ensure that I am at least breaking even.
This image will show you an example report
And at anytime I want I can go into my backend and print off a report for certain regions, dates, spend limits, and I can see anything that is costing me money.
The thing about this is that, you have to know what you want and how you want it to work. There isnt a web developer alive with business skills that will match those of a seasoned pro, so you have to tell them what you want or you wont get it.
The only other thing that might be helpful to you, and I dont know beceause I dont use it is a program made by google called
Google AdWords Editor
It can connect to your adwords account, download info, you can make new campaigs through it etc.