Hey,
You can do Masters in Economics even if you have English as your GE.All you need to do is to select Economics as your specialisation subject in your 3rd year.
B.Com that is,Bachelor of Commerce is a three year programme.When you enroll in B.Com Honours you are taught subjects like Accountancy,Economic,Statistics,Finance and some more and in the final year students can choose any specialisation subject in which they want to pursue Master degree in future.
Hope this helps.