Did you look at
www.bookings.com ? There really aren't many hotels around Bogenhousen.
For Munich plan you can look at this website (it's in German, but quite straight forward to use)
http://www.stadtplandienst.de/
Another good source is local Yellow Pages (
http://www.gelbeseiten.de/) just enter hotel in 'Was:' and Muenchen, Bogenhausen in 'Wo:'.
I noticed that there is Holiday Inn near-by, it's not so cheap, but cheaper than Arabella Sheraton.
I'd personally suggest to look for hotel in Schwabing and just take a taxi (or public transportation).