refer to the T2 sponsor guidance:
http://www.ukba.homeoffice.gov.uk/sitec ... iew=Binary
para 683 and onwards about licence suspension
para 599 about supplementary employment
It is not possible to forecast the outcome of your sponsor's appeal but it can be:
(a) re-instatement of the licence
(b) downgrading to B-rating with an action plan
(a) withdrawal of the licence
They will only be able to assign a CoS in case (a) or in case (b) if on completion of the action plan they get back their A-rating. You would need a new CoS for the extension.
What happens with your leave will depend on the ouitcome of the appeal and how seriously your non-compliance with the rules is viewed by the HO but if you leave the UK and apply for entry clearance you are likely to be subject to the 12 month cooling-off period unless there is a ban imposed on your return for a different period.