Auto Ad Replacement Software

Am in need of an program that opens as an executable, This program will silently run in the background of my computer and it will replace every advertisement code with my own advertisement code. For example if i was to surf to [login to view URL] and there website contains an advertising banner on top of the page, Id like the program to see that and automatically replace it with my ad code, Within the settings i'd like to include 5-7 different sizes of banners so i can simply copy & paste the banner's HTML code in the box and the program will replace with that exact code. I understand this project can be completed in .NET however since my goal is to keep the output stub (.EXE) size as small as possible i'm open to other native languages that can do the job. If you're not experienced or are just looking to make a quick sale then please DO NOT waste my time with pre-writtened responses. No offense but no Indian coders, I've had terrible experiences in misunderstandings with them. Thanks again!