Get a new adapter...
You can pick-up a Tivo wireless b/g off ebay for $10 - $20.
Faster wireless is always better. However, you have to ask yourself: how are you using the Tivo? If you're using the Tivo to get scheduling then stay with G. I'll venture it takes less than 30 seconds of "network" time to get schedule information. The system preparing the scheduling query takes a minute or two, and won't be impacted by any network adapter.
If you're using the Tivo to watch Netflix or Amazon to go, then the network adapter becomes more important. However, your landlord's network speed is more important than the adapter. I've had no issues with either over "g".
If you're using Tivo to go, your adapter screen is critical. However, if you can get Roxio Toast to work I'll tip my hat to you. The program, once a top tier one, is now virtually useless for many things -- but that's another story and unrelated.
Whilst I have no experience with the Tivo "N" adapter, there's a lot of reports of it being quite persnickity, and requiring the occasional reconfiguration to work. Take this paragraph sceptically as it's based on other's reports (which may or may not be valid.)
Good luck.