Hi,
Let me ask you a question first...
Do you understand basic circuit analysis, such as Nodal Analysis or something like that? Most of your questions involve looking at the circuit and calculating some voltage or current, and it would help a lot if you understood basic analysis a bit better.
With 1v into the left buffer, we get 1v out. With 0v into the right buffer, we get 0v out.
If we have two 1k resistors in series connected across the output of these two buffers, we must get (1-0)/2000 amps out. That's 0.5ma. If not, then something is really wrong. That's when you start checking voltages and connections and simple things like that.
See if you can find something simple wrong.
The simplest explanation of a current mirror is that it is a "current controlled curent source" that puts out the same current as it gets into it, so it's got a current gain of 1. So the output current is the same as the input current, as long as it is held within some limits such as output voltage and temperature gradient and stuff like that.
So a current controlled current source with a gain of 1. Current flowing DOWN in the left side will also flow DOWN in the right side.
A little more complex explanation is that the input transistor gets a current, and because it acts like a diode that particular current results in a particular voltage across it. That same voltage is then applied to the other transistor, and because that transistor now has the same base emitter voltage, when the collector is at the same voltage as the first transistor the current in the second transistor has to be the same as it acts in 'reverse' of the first transistor. If the second transistor collector voltage is not the same as the first (as is often the case) then the second transistor does not mirror the current *exactly*, but there will be a small error due to the Early effect. The four transistor current mirror attempts to make up for this effect, but because it is small you may not have to worry about it at least not until you get everything working right the way it is now with the simpler circuit. There are other errors too but we dont worry about them right now.
So you see it gets more complicated, but thinking about it in terms of a current controlled current source with a gain of 1 should suffice for now: "whatever current goes in one side comes out the other side".