This is w-a-a-a-y out of my league, but I Googled 'Tivo RF remote extender' and found a couple but it seems 'not currently available' which has been inflicted on a lot of things lately. There is also some chatter about a remote IR receiver that plugs into the box. Beyond any of that, I'm out. Good luck.
Your best source of information is going to be Tivo. Low power transmitters can operate in different frequency bands, so finding a "booster" would not be easy. Particularly since they will likely be brand specific because there are just too many variables involved.
A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Come join the discussion about tools, projects, builds, styles, scales, reviews, accessories, classifieds, and more! Helping You to Do It Yourself!