How can I increase the number of tuners - DirecTV

Hello, I have a genie system with two mini clients, two hd dvr receivers with i believe to be a swm 8 way splitter thing. I also have a hd dvr receiver thats hooked up to a separate dish in my garage. I want to bring my garage receiver in for the winter and connect it to my swm splitter but when i do it wont work. My friend said i should get a bigger swm splitter. Is he correct and is this something I should try to hook ip or just have dtv do it? Thanks in advance for any advice

This question, "How can I increase the number of tuners," is about DirecTV channels, programming, equipment, and sports.