If you perform duties as mentioned under NOC-0213 ( atleast 75%) then you are good to apply, designation does not matter.
Approx time varies from 12-18 months.
You don't need to go with any consultant, go over the CIC immi website do some google and read some forums like this and you will be a consultant for your self

If your mother tounge is not english.. better to give IELTS , even you have good points (over 67 without adding english marks) good to have IELTS score.
good luck