Help with updating rooted Nexus One

[Guest kesi]

Hi, I had a few questions about how to apply the update to my rooted Nexus One

I followed these directions to unlock my bootloader and root my phone using Amon RA and Cyanogen's N1 addon:

http://androidandme.com/2010/01/hacks/vide...ot-a-nexus-one/

Now I am unable to get the update manually or automatically. So, from what I understand, I have to flash one of these images but I'm not sure which one to use:

http://android.modaco.com/content/google-n...insecure-himem/

Questions:

1. Which of these should I use to get the update + root access?

2. Will this wipe all of my apps and settings and, if so, is there a way to back those up?

3. When I rooted my phone, I seemed to lose some contacts - specifically those I had added to imported facebook contacts. These are also not backed up to my Gmail account for some reason.

Details:

Firmware Version: 2.1

Kernel Version:2.6.29-bacon1\shade@toxygene #1

Build Number: ERD79

Let me know if you need any more info and thanks!