Not to confuse you further, but are you sure you have the right village? There is another place of the same name, also in Wielkopolska - it currently belongs to 'Parafia św. Andrzeja Boboli w Poznaniu' (Parish of St. Andrew Bobola in Poznań).
Anyway, I'd opt for emailing the 'suspected' parish - the priests should know the local history and are quite likely to be able to point you to where the records are stored (which in either case is most likely the Archdiocesan Archive in Poznań). For the parish in south Poznan (which used to be in Komorniki): http://www.parafiajunikowo.archpoznan.pl/kontakt/ For one likely to cover Rudnicze near Wągrowiec, try the parish in Wągrowiec http://wagrowiec.paulini.pl/?page_id=65
In many cases, identifying the name or extent of a parish will depend on the religious denomination and the time period. A parish may also have some civil scope (as in Louisiana).
I think in this case we can assume you mean the Roman Catholic parish, instead of the Lutheran parish, and that the time period is around 1900.
Kartenmeister has 2 entries for Rudnicze:
Wongrowitz is now Wągrowiec; Rogasen is now Rogoźno
[The Google map link for Rudnitsch is wonky, but I've found this database generally reliable for its data]