One of my biggest complaints about Blackberry was the pathetic ringer/notification volume; combined with the wimpy ringtones it was impossible to hear in anything other than a quiet office environment.
I would suggest trying custom ringtones/notifications and see if that improves the situation. If not, you might want to take a look at MP3Gain - a Windows app that allows you to increase the inherent volume in an MP3 file. I used this with my Blackberry and it helped quite a bit.
If none of this helps, you could try tracking down copies of Nextel ringtones and using those as your custom ringtone. Somehow they sound louder (to me), possibly due to the frequencies they use. When I got my OG Droid, one of the first things I did was capture the ringtones from my Nextel phone and add them to my Droid.
Okay, this is my second android phone and first tablet. I still MISS my Windows phone. I have not found a way to sync with Outlook (I'm not happy having to put all of my personal information out on the internet to Google). The ringtones and reminders are horrible. I have a disabled person that I take care of and use to use my Windows phone for all reminders and I could hear the phone from my basement to upstairs when I had reminders or calls; I loved it.. If I can't find something similar with android already I'm going to have to try to find another windows based phone or a blackberry. I've tried downloading the medical minder and don't hear it half the time so I'm having to set the timer on my stove.