|The D-Link 614 can only be used as access point.|
So hopefully your Belkin Wireless N router supports repeater mode.
In repeater mode, the Belkin router connects to the D-Link router as a client, just like a notebook would do. But we talk about repeater mode, that means, you can also connect to that Belkin router wirelessly. The Belkin extends the wireless network of the D-Link router.