First time I've used Avant since I started using a Macbook 5 years ago. Now, with my pc laptop I'm back with Avant and found that it has changed. There used to be the word "Tools" up top. No longer. Shouldn't be so hard to find, it should just be there. And you shouldn't have to run a search to find out how to change the search engine.
It's a bit tricky but I'll try to explain.
Click Tools -> Avant Browser Options.
In the left field of the window that appears choose category: Search Engine.
Two tabs appear in the right field, Quick Search and Standard Search. Click the Standard Search Tab.
Now, presuming you like Google, paste http://www.google.com/search?hl=en&q= in the top row marked Web instead of AvantFind. Done!
(In case you like any other language rather than english replace "com" and "en" with language of your choice)
Swedish Google will look like this: http://www.google.se/search?hl=sv&q=
Hope this helps...