I understand that you want to know if you need to get the SlingLinks if your router and the TiVo box are located in different rooms.
Before you decide to get the SlingLinks, there are some very important details you must know about them.
The most important thing is to determine if both of the rooms go into the same electrical phase or circuit. Why is it so important? Because the SlingLinks will work with your home wiring system in order to "talk" to each other. If both of the rooms go to different electrical phases, they will never "talk" to each other. The following links will provide you with all the information about the SlingLinks and how they work.
Once you have checked all this information, you will be able to decide which SlingLinks version is the right one for you. No matter which version you purchase, it comes in a two-units set. Then, if you want to connect only the Slingbox, your best option is to get the one port version. On the other hand, if you want to provide Internet access to more than one device, you best option is to get the 4 ports versions.