Ubuntu 10.04 and HP Envy 15 (1st gen)

Dear community, I finally moved to Ubuntu at my home laptop and faced couple of problems I'd like fix.
I've searched through the forum and all posts related to HP Envy is dated to the time when 10.04 was still in development and actually still didn't find an answer.

So I have 2 problems and 2 thing that is nice to have working;

Problem #1:

Not surprising according to the forum, but it's ATi 4830, and exactly the proprietary driver. I've tried to install the one that Ubuntu suggest right after installation and one from ATi web-site. Both causing Ubuntu to stop loading. After Ubuntu-suggested driver I was able to get it back working, but after ATi I cannot find a way to get it back.

What is the correct way of restoring to the state without ATi driver and how to make it work? I need it because battery life time is very poor with GPU working at max performance all the time.

Problem #2:

As you might know HP Envy have dual-microphone system. Looks like it's trying to use second microphone (noise cancelling) for capturing sound and the quality is veeeery poor. There are no options to choose which microphone to use (at least in GUI). Is there a way to fix that or in best case use dual-microphone scheme with active noise cancelling?

This two points are quite critical, but there are two more things that would be nice to have working.

Wish #1

Ambient Light sensor. Is there a way to utilize it under Ubuntu? It's a quite nice feature and really helpful. Any comments or suggestions are appreciate.

Wish #2

The multi-touch for touch pad. First when I just bought it I hated this feature, but now so get used to it. Is there any way to utilize it as well in Ubuntu?

Any comments, links, FAQ or whatever are highly appreciated.
I don't have deep knowledge in Linux yet, but playing around for some time on my virtual machine at work.

Thank you in advance for your help.