How do I downgrade Minecraft

[cmhcraft12]

Hey, guys. I just got the new 1.4.4 update, when I learned that I couldn't connect to a LAN World because I use an HP laptop with Windows 7, and my brother kept his .jar, as we use the Magic Launcher.
So, just a second ago, I found that there is a new update to the Pixelmon mod, but it's only for 1.4.2... I don't know how to LEGALLY get a Minecraft jar folder so I can get 1.4.2. Any ideas?

 

[RedSeamonster]

Here you go.

 

[cmhcraft12]

Here you go.

Actually, I already got it. I probably should've said that before.
But thanks, though!