I did not see an answer here for this so I'm posting how I figured it out. Go to your admin >general setting > product search options and turn on the extra fields you want to use in quick search.
Then go to advance search on your site and look at the source code. Find the extra product fields.
Code:
<td width="5"><input type="checkbox" id="ef_1" name="posted_data[extra_fields][1]" checked="checked" /></td>
<td><label for="ef_1">Colors</label></td>
Find the field you want like posted_data[extra_fields][1] and then put it in your quick search like this
Code:
<input type="hidden" name="posted_data[extra_fields][1]" value="Y" />
Hopefully this helps