Android 2.1 integrating Push and/or Pull

I have been building an Android application 2.1+ and need someone to build a push/pull facility. Basically we will be using C2DM for pull on Android 2.2+ however, for 2.1 we will need a pull. All API's are setup and deliver XML. We will need to receive the push notifications, then download the necessary data. At this point i've already build a system for parsing that data and inserting it into the local database. I'm hoping if the application is open when the notification arrives we can download the information in the background without disturbing the user (is that a good idea?) maybe a simple warning - 'You've received some new information'. As for Pull, in Android 2.1 we will still need near instant data, so maybe a pull ever 5 minutes which looks at the webservice, downloads anything if there is anything else goes to sleep. If it finds anything a similar behaviour to push would be required. The basic idea is the user doesn't really see much of a difference in either approach apart from battery consumption and speed of data arrival.