Specifically can't find this cpu choice now.
... look at this screenshot
guest x11 resolution not right,
You have to install GuestAdditions. Please read in VirtualBox manual> 4.2.1. Guest Additions for Windows
don't know how to export final iso to host,
First of all you have to copy the new ISO to the directory of isoimages from VirtualBox. Don't know how this looks like beneath Windows7 and how you can do it. Perhaps you need an USB-stick to make the copy from VirtualBox to the directory in Windows. With Linux it is all very easy to do

After this you can mount the new ISO in VirtualBox to start from it.


Greetings Werner * http://www.wp-schulz.de/knoppix/summary.html
Own Rescue-CD with Knoppix (Knoppix V6.4.4 remaster)