How to communicate with the arduino

REASON:
I’m about to do a mashup of the office coffee maker and an arduino. I want to get the coffee maker to tell me when it’s on/off, how long it has been on, how much coffee is in the pot and how hot it is.

BASIC INFO:
All that should be fairly easy to solve but my problem is rather the communication. From my room to the kitchen it’s roughly 15 metres but the only open space is a narrow hallway. In other words alot of walls to penetrate. Most our wifi users have a problem with these walls.

QUESTION:
What would be the ideal way to communicate with the arduino in this environment?

REGARDING WIFI ISSUE:
Regarding WIFI, since I do have a valid reason to do something about this, please dont refrain from suggesting it if you think it would be the best solution.

http://www.ehow.com/how_4662693_use-ethernet-over-power-outlets.html

How about something like this...

http://www.sparkfun.com/commerce/product_info.php?products_id=8946

You could try using Xbee - Xbee comm using a more powerful module:

Or you could go for a 1 mile transmission range :wink:

Thanks for all the tips. Unfortunatley those really cheap RF modules were out of stock. However I will definitley look further into both RF and Xbee communication but first of all I think I might try out if my phone can reach my desktop via bluetooth. If that works I might aswell buy the sparkfun BlueSmirf module.

Theer are lots of suppliers of the RF modules, they are very common. Just do a search in Google.