The prevailing thought is that an extention is probably what will happen, rather than a new bill. Senator Boxer maintains that as much as 80% of the bill is worked out but there are big unresolved differences such as environmental streamlining and Keystone XL.
The question now is apparently the length of the extension. There is apparently the risk of a gamble that would cause the US Department of Transportation to shut down for a time. Anyway, read the story at the link ahead to see all the variables involved in getting either a new bill or an extention passed.