Tier 2 ICT Extension timelines

[kattang]

My Visa Expiry Date : 21/2/13
CoS Expiry Date : 21 /1/13

I had applied for extension through in person appointment but was refused because my Extension CoS had expired . This was on 07/02/13.

Can i resubmit my extension application now with a fresh CoS before 21/2 ?

In general what date needs to be considered as deadline for applying extension , CoS enddate or Visa Enddate ?

[Gagan1986]

Make a fresh application before the end of your visa expiry with a renewed COS