Oh goodness AB the agony of waiting...
Just so you know - the full results of the amnio do take a week as they test for a number of genetic conditions not just Down Syndrome. However they can do a "fish test" which should take less than 48 hours and this will give the results for DS only. You should ask for this.
The reason for bedrest is that there is a very small chance of miscarriage following an amnio - I'm sure you are aware of this already? The chance is lower when done in a facility that do amnios routinely, so from that perspective you may be lower risk in Auckland.
I don't know what else you have heard or want to know but I had about 20 weeks of investigating matters relating to DS so found out quite a lot of stuff. You have probably had a look on the internet and talked to your MW etc but do feel free to ask me any questions too.
In my case I was convinced (despite the 1:20 nuchal test result, and signs of a blocked kidney at the 19 week scan - which has some correlation to DS) that my baby was NOT DS, and in any case had made a decision to keep her regardless (personal choice) so I fought like mad not to have the amnio as I didn't see the point.
The ob/gyn tried her absolute utmost to force it upon me the same day I first met her (which was actually at the 19-20 week scan). Ironic how different situations pan out isn't it. I resisted and resisted (until 32 weeks actually) until my Mum finally convinced me it would be good to know "for sure" plus I had a huge build up of amniotic fluid which really needed to be released.
The ob/gyn was so sure that DD2 did have DS that when the results of the amnio came back clear she wanted me to have a second amnio on the basis that my blood must have contaminated the sample somehow. She also "claimed" to see signs of a heart defect, told me that the 32 week ultrasound showed DD was a boy (even though I'd had 6 prior ultrasounds where I'd been told she was a girl)... I could go on.
Its all a long time ago now but I must admit I still have some residual anger over the way she treated me.
I absolutely agree that having decided to go ahead and have the amnio the days of waiting were absolutely the worst. Take care of yourself.