Windows minGW g++ version 3.4.5

[PUK_999]

I've installed Qt under Windows. Qt installs mingw for me. Dropping to the Qt command prompt and typing g++, I see the following:


C:\Qt\2009.03\qt>g++ --version
g++ (GCC) 3.4.5 (mingw-vista special r3)
Copyright (C) 2004 Free Software Foundation, Inc.


I'm more familiar with the Microsoft compiler world of things, so forgive me if the following questions are silly:

1. Does that mean Qt 4.5 on Windows is tied to g++ 3.4.5?
2. I read somewhere else that g++ (gcc is the same thing, right?) is on version 4.4.1. Why such an old version?
3. Is it possible and trivial to upgrade the compiler if necessary?
4. What if I was to use some third party piece of software that only works on gcc versions 4 and upwards?

Thanks,

PUK