how to publish an update to application on the android market?

Question

I already have an application on the android market and now I want to upload an update to that application. I have made the new application with the same package name, I have in

Answer 1

Might be too late but:
Once you're logged into the Android market for publishers, click on your app under "All Android Market listings", and click on the tab "APK files".
Then you need to deactivate the current published apk version (click on "deactivate"), upload your new APK (click on "upload APK"), activate it (click on "activate"), and click on "save".
You don't need to unpublish-publish at all (if all you want to do is update your apk).

So, you don't need to upload your app as a new app, you just update the existing one.

Note: You can't delete the older versions of your apk, they're staying there for you to be able to reactivate one of them is need be.