Assuming you are talking about Gmod 10 (latest) and you already have the models installed, you can simply go to the props tab in the 'Q' menu, find the right category, (e.g. HL2 Characters) and spawn it like a prop. If you cannot find the rag doll in the props tab, i suggest clicking the browse tab and searching for the rag doll you want that way.
press and hold q and a menu should pop up and click on characters and select one.
Buy Garry's mod 10 off of steam.
technically yes, there were a few updates it is still called Garrys mod 10 though
Garry's Mod 10
no because garrys mod requires that you have a game that uses the source engine
Garry's Mod has now updated and includes all features of 13 Beta
Garry's mod tornado
Steam
yes
You Do Not Get Garrys Mod Serials, You Buy it Off Of Steam Which can be found at steampowered.com its usually about 21 United States Dollars
E
no
You can't