iMacros script needed

Hello, I need an expert which can improve my iMacro script. I have a script developped with iMacro on Firefox which basically go to a URL, there is a subscription form there with name, email, ... All info are on a txt file, the macro fill the form in and submit. No problem on this side. I need to optimize it by creating a loop. Once the form is completed and submitted, the script has to take line n+1 from the file, go to the url one more time (open new tab/browser and delete cookies otherwise the web page will detects you already visited the site). Please note that after submitted the form, I have a tool which change the IP. Go to URL --> copy/paste info from txt file --> submit --> change IP --> open new tab/brower --> clear cookies --> restart