Need motivation from Mom's 20-25!

Hi,

I'm Lauren. I'm 23, and have an 8 month old baby girl. While I was pregnant I put on 20kg's. I have lost 12kilo's so far but am struggling to shake the rest. Can you please give me some tips on diet, exercise etc? Would much appreciated! I still need to lose 8 kg's by X-Mas to reach my goal for this year! I'm worried I'll never be able to achieve a flat stomach as I have got pretty severe stretch marks, and the skin is still really loose. Please help?

Cheers.
xox