1) All DBP applications require an installation of DirectX 9.0c Aug 2007 or later.
2) You simply have to posses it. I recommend saving your money unless you're absolutely sure that you will release a game. Less than 3% of games made on this forum actually get finished.
3) YES it is totally a good modelling program. There is a custom DirectX exporter for it somewhere on these forums, you might want to check that out because 3DS files don't support animation as far as I know.
TheComet
"Why geeks like computers: unzip, strip, touch, finger, grep, mount, fsck, more, yes, fsck, fsck, fsck, umount, sleep." - Unknown