Hi Wayne,
Adding the ability to include attachments in emails sent from Method requires customization. I wrote a post for adding this functionality to the list builder screen yesterday. You can take a look at it here. This can be easily adapted for use with the activity screen. Feel free to reach out to one of our partners or your account manager if you would like some assistance with this.
The Gmail gadget is made for use within Gmail. You would simply send an email as you normally would through Gmail and the gadget will allow you to create a Method activity based on the sent email. You can read more about the gadget in our Help Center.
I hope this helps.
-Audisho