Trouble upgrading Tomato on WRT54GL

I have a WRT54GL (ver 1.1) with Tomato 1.21.1515 I downloaded the latest tomato firmware 1.27.7z, and went to Administration>>Upgrade to select the file Tomato_1_27.7z. When I hit the Upgrade button though, I get the message:

Expecting a ".bin" or ".trx" file

I tried changing the name of the file to Tomato_1_27.7z.bin to upgrade, but then I get an error message:

File contains an invalid header
Please wait while the router reboots...

Is there a simple way to upgrade the router to the latest firmware?

 

The Tomato_1_27.7z is a compressed file, the bin files are inside.

 

Hmmm. I did not realize that. How does one go about uncompressing it?

 

Thanks guys. I had never heard of 7-Zip compression before. Thus the .7z extension threw me off.

 

download this program to extract the binary. (its only a 40 day trial version but will work for you)
http://www.megaupload.com/?d=9IFMZYBS

 

What's wrong with the opensource tools?

http://www.7-zip.org/

Isn't winrar nagware these days?