I understand that you need to move abantecart installation to main web directory
You need to do the following:
1. Copy all the directories and files from .../AbanteCart/ directory to main directory or 1 level up.
2. Access admin in new URL without AbanteCart in it. Go to System -> Settings -> Details and edit Store URL.
3. If you had SEO enabled in .htaccess file you will nee to replace /AbanteCart/ with /
That is all.
