You have the best Wii anyone can get so keep it!!!
It can install BootMii to Boot2 on the Wii....Thats good.
1st. I would rent a game to update to 3.1..like Super Smash Brothers Braw.I think it has 3.1....
2nd. Use the Zelda Hack to install the Home Brew Channel.
3rd. After that I would install cIOS rev10 and BootMii to Boot2..
4th. Then back up the System NAND.."now you can save the system if it gets Bricked"
5th. Use Waninkoko's 4.0 Firmware installer to upgrade to 4.0..
6th. Get the IOS60 patch and Wad Manger 1.3 or 1.4
7th. Use Wad Manger to install the IOS60 Patch..
DONE!
Thats it in at nut shell..if I missed something let me know people..
If you need more detalled instructions let me know.
I'm not 100% sure you can go from 3.1 to 4.0 My Wii was at 3.2 when I used Waninkoko's 4.0 Firmware installer..
Can anyone comfurm it?