There are bigger issues to consider when crossing platforms than wireless vs. 30 pin. One huge drawback for Android is device/os fragmentation which makes proper, medical grade, testing very difficult, time consuming, and expensive.
Just to clarify, does the iBGStar device perform the actual test and then the result is transferred to the iPhone, or is the iPhone actually part of the result computation process?
If the former, I can't see how transferring the results to an Android phone via bluetooth or USB would cause any problems and it would be extremely simple to end up with the data in an SQLite database for analysis using a very simple front-end app.
Having just an iPhone-specific product seems to limit your potential market considerably.