I recommend you download GM2.2, it seems to be "snappier" grabbing GPS info. Once the tower-based location service support had launched, I had experienced a 1-2 minute delay before it zeroed in on GPS. This was the case with 4.1, 4.2 and 4.3, not just with 4.5. Download the new version as soon as you can!
Also, for the troubleshooters out there, had no issues w/Google Maps on 4.5.0.37 on my 8110 OR 4.5.0.1 on my 8310. When I first switched to 4.5, I was rocking Google Maps 2.0, then 2.1. I never had to do any tricky OS edits, etc. I hope this helps...