New Job, Tier 2 General Refusal, How long do I have?

Hello,

I found a new job and applied Tier 2 general visa on 27th of January 2015 at Premium service centre, but it was refused because my sponsor used a wrong job code on CoS. I still have leave to remain until 2017 therefore I only can make a fresh application.

I am no longer working with my previous company, but they have not reported to Home Office yet. I am still awaiting CoS from my new sponsor.

My question is, how long do I have in this case? My current visa is based on the fact that I'm working for my previous company, right?
If my previous company doesn't report my leave to Home Office, does that mean I don't have any deadline to apply the fresh application with my new sponsor? If Home office find out that I'm not working for my previous company when I apply the fresh application, what is going to happen?

Please give me some advice, it is extremely frustrating not knowing when my deadline is!

Thank you so much in advance.