Directv On Demand & Slingbox Powerline Adapter?

Hi. I'm hoping someone can help me with this. I'm trying to get my DirecTV HD DVR (HR-21) connected to my internet connection. I currently have my slingbox next to the HR-21, which is connected to the internet via a Slingbox Sling-link powerline adapter (the other powerline adapter is in the room where my internet connection is based, and is plugged into the wireless router via ehternet cable).

I'm wondering if there's a way to connect BOTH the Slingbox and the HR-21 to my internet connection with the current configuration or if I'll need an additional internet adapter.

As an aside, I unplugged the Slingbox earlier and plugged the ethernet cable into the top ethernet port on my HR-21, and when I went to the Network menu, it said that it was connected to the network but not to the internet. I restarted the box and my wireless router to no avail.

Thanks in advance. Any help would be GREATLY APPRECIATED!