Sorry, I guess I left that little detail out 
Yes, the 702 has an English web interface.
As I said, the 703 router comes in AP mode. If you want to integrate it into your home network as shown in your little " sketch" then it is easiest to switch it into "bridge" mode. So Google Translate is your friend.
I'll see if I can find the file I generated with open office where I wrote down part of the menu structure that I translated with Google Translate. If I find it I'll post it here. After all for the price of the 703 - I think I paid $26 for it on eBay - it's a nice piece of equipment and this MIT be useful to someone 