Temperature is a measure of the amount of energy in something.
Yes absolute zero is the lowest temperature possible because by definition there is zero energy. You can't actually get to zero energy because when you get very low you start to get tiny quantum fluctuations that give you a very small tempreature.
Temperatures down to 200 billionth of a degree above absolute zero were managed about 10 years ago to get a new phase of matter called an Einstien-Bose Condensate and that was beaten again a few years ago at 50 billionth of a degree to get something called a Fermionic condensate.
This is massively colder than anything you'd find anywhere in space
I can beat Lord Molly's 12million degrees with 2 billion degrees:
http://www.livescience.com/technology/060308_s andia_z.html
The problem with very high tempreatures is that you have to start being careful about what you mean.
Normally we think of temperature as a measure of how much the atoms and molesules are bouncing about. Already at these temperatures the atoms have broken into electrons and nucleii. When we look at the collisions in nuclear accelerators we see that when subatomic particles hit eachother hard enough they are distroyed and new and short lived exotics come into existance.
In these sorts of collisions, which are like the conditoins in the early Universe the idea of tempreature becomes a bit meaningless and we start talking about the energy of the particles.
The new accelerator at CERN will be able to give particles 14,000,000,000,000 volts worth of energy (14TeV) which if you stretch the meaning comes out at a few trillion degrees