Only you can answer that. What is your intention after doing 70-433? If you are looking to get MCITP, and then use that to transition to MCSE, then it's worth it - there's a lot of core topics covered in 70-433 that are relevant for all versions of SQL Server If you haven't got the time to do MCITP before end of July, then maybe not. If you are looking to get 2012 certifications, and haven't got any 2008 ones, then you may as well start on the 2012 path (with 70-461) as the number of exams to MCSA or MCSE is the same as the upgrade path.
I did 70-433 och 70-450 to get the "easier" upgrade path for SQL 2012. You can skip MCSA and go straight for MCSE if you do like me. I would say, if you have to study a lot for the 70-433 and 70-450 then maybe its better spent time to go for sql 2012.