google conversion tracking issue

I'm relatively new to rails.
I want to place conversion tracking code on a site, on the
confirmation page for signups and sales.
I have separate code for each type of conversion, but I cant figure
out how to place it so it works. The same page is used for signups and
sales, using conditional statements to determine whether it displays
confirmation about a signup or a sale. I tried putting the code in the
conditional statements, so that it would track the right thing. I was
able to try test conversions for signups, and when I viewed the
source, i saw the code snippet, but it didnt display the google stats
text box thing that is supposed to be displayed on the confirmation
page. Also, no conversions ever showed up in the adwords report. It
stayed at 0.
I think I must have placed the code in the wrong place. I read on
google that it needs to be placed in a portion of the page with static
html, but the page is dynamic, and it depends on which activity you
are doing what it displays on the page.
I would greatly appreciate your help.

U don't have modify any code in rails. I have installed restful auth
plugin so I know users who complete the signip process will go to /
users URL. I have setup a daily report via google analytics that
isvsent via email. It shows me the percentage of users who reach that
page. So I know the conversion rate is very close to that figure.