The features are
- Intel Core i5
- AMD Radeon
acpiz 55°C core 0 55°C core 1 56°C core 2 54°C Radeon 66°C
Is that ok, what can I do? This did not happen on Windows 7 and the laptop is a new brand.
I know this is quite a late answer to your question but in case you still were having these issues and needed an answer:
Having a laptop overheat is never a good thing, although when running CPU/GPU intensive tasks I don't consider going up to 55°C-60°C as being too excessive, as long as you don't stay above that limit for too long you won't damage your hardware as far as I know.
If you'd like to be able to regulate this and make sure that your laptop stays quite a bit cooler when not doing anything particularly CPU/GPU intensive. I'd recommend an applet called Jupiter (here's a quick introduction explaining what it does).
The official Jupiter applet site also gives you some clear information on what it does, I've taken a screenshot below to save you a click:
To give you an idea of what reducing my CPU usage has done:
On average when not in "Max Performance" mode my CPU temperature is 37°C, I used to have similar temperatures to your laptop beforehand and I've found from personal experience that it greatly improves your battery-duration as an added bonus when on the go.
I've tried this on my HP pavillion DV6000 in case you were wondering, so going by the assumption that similarly branded laptops will work in similar ways with this applet I'd give it a try.
Heres the site if you want to add the PPA to your Ubuntu distro and give it a try, I wasn't expecting much when I did install it, but it turned out to be the best power/heat management solution out there (as of 31/10/2012).