Android - change package for same app - redirect

We have this problem
Our app was originally created by an external company (therefore a key owned by them is needed for signing the .apk file every time we want to upload a new version)
Now we started to develop our app by ourselves and want to release this app but at the same time keep all the traffic and the reputation of the former app.
The app/service/name will be the same.
We basically just want to get rid of the first app package and upload new one to be independent from the external company who developed the first version.
The questions are:

1) Since we have a lot of links (blog - press release - website) on the Internet pointing at the "first app", is there a possibility to keep the same old link for the new app or alternatively get a redirect?

2) If the 1)solution is not working, is there the possibility to keep two identical apps for a limited time period necessary to inform our users they have to download the new app and inform all the press websites to change link?

Thanks in advance for you help!