It sounds like you only have one receiver:  the Motorola VIP DVR.  You cannot replace that with a wireless receiver.  The wireless receivers are STB's only not DVR's.  

Since you only have a DVR and no regular receivers, you will need to keep the wired box.  You can use a wireless receiver if you want to add another TV to your system.  You can have up to 2 wireless receivers in your U-verse setup.