[DEL]Its there already.(SegoeUIsym.ttf) However you need to use something like charmap to view it. Alternatively a file manager like 7-zip will show the font file in the Windows\Fonts folder. Explorer will not open the fonts folder as a normal file folder - it opens it in Control Panel instead, hiding many of the system fonts and only showing the basic character set.
(The segoeUIsym.ttf in Windows 7 has not got the metro tile icons set in it. Perhaps if the Windows 7 file was put in the Windows 8 Fonts folder it would thoroughly trash metro - anyone up for it?)[/DEL]
That wasn't very helpful was it? Sorry, I should have read the original post properly.
You need your original install media for windows 8, and something that will open the /sources/install.wim file. I would recommend 7-zip:
Download
With 7-Zip installed, navigate to /sources/install.wim and right-click it. Select the 7-zip option on the menu, and open the install.wim.
In the 7-zip file manager navigate to windows\fonts, and find seguisym.ttf.
Simply drag it to your desktop. You can close 7-zip. Right-click the seguisym.ttf file on the desktop, amd select install, and replace any version that may be there already, and you should be ok.
I'd reboot, then check out metro.