Hi, i have had my ds fat, from launch .The touch screen is getting a bit broken.So i plan on upgrading to the dsi xl mario red one. 
I dont care about 3d,so should i upgrade to dsi xl or just leave it

Just wait for the 3Ds at this point. You may not care about 3D itself, but a new Nintendo platform is hard to not at least wait for.

Well even if you don't care about 3D I still think you should wait for the 3DS. All the new titles will be coming to the handheld and the 3D can be turned off. Maybe pick up a Lite for cheap to last until the new console launch.

If I were in your situation, I'd get a DS Lite unless you really want the larger size screen. They're cheaper and the DSi features really aren't worth it.

The 3ds will be basically a new generation ds with more powerful hardware. So if that doesn't matter to you either, I guess go for the xl.

The Ds Lite was a pretty essential upgrade from the phat, but the DSi was just an incremental improvement and the XL is only needed if you need a much bigger screen. DSi already has a bigger screen than the original.
 
The 3DS will be expensive but it will be backwards compatible. If you are thinking of getting any of the 3DS games then wait but otherwise I'd advise getting a DSi.

I sold my DSLite and upgraded to a DSiXL (the SMB Edition one). I had not played my DSLite in about 9 months. The XL version actually is comfortable to play on due to the larger size. It makes me want to play my DS games again... (Metroid Prime: Hunters was painful t play on a DSLite Plus, the screen size is a great improvement in both size and quality. I am not sold on the 3DS yet, and I know they will come out with an XL version of that; so I won't be getting a 3DS for a year or two after it comes out. 
For me, the DSiXL was a great buy, and made me want to pick up my Nintendo portable again. Plus, we all know how many different versions and tiny upgrades Nintendo will make with the 3DS; so you'll have plenty of time to make the purchase worthwhile as you choose your new color.