When a VM is not on the same network as the host machine, you can setup a virtual adapter to facilitate copying of files from the host to the VM and vice-versa.
Go to hyper-v manager and click "Virtual Network Manager" from the right hand pane. With the subsequent dialog, select "New Virtual Network" –> "Internal" and click add.
Give the new network a suitable name and click ok.
This will create a new network adapter on the host machine that you can assign a static ip (quick and dirty method to get this working). Select start –> settings –> network connections and select your newly created network adapter. Right click in and select properties. From this, highlight Internet Protocol (TCP-IP) on the General tab and click
Set the IP address to something like 10.10.13.1 and the subnet mask to 255.0.0.0.
You now need to add a virtual adapter for your VM to connect to this newly created network. To do this, you must first shut down your VM. Once down, right click to select it in Hyper-V manager and select Settings from the context menu.
In the settings, select "Add Hardware", then select "Network Adapter" and click the add button. From the subsequent network dropdown, select the name of your newly created internal network. Click ok.
Start you VM. Within your Virtual Machine, select start –> settings –> network connections and select your newly created network adapter. Right click in and select properties. From this, highlight Internet Protocol (TCP-IP) on the General tab and click
Set the IP address to something in the same ip range as the one you have just configured on the host machine (e.g. 10.10.13.2). Set the subnet mask to the same as above – e.g. 255.0.0.0
Click ok if you are prompted that dns entry is empty.
You should now be able to connection to the host machine from the VM by typing \\10.10.13.1\C$ into explorer.