Hardware and performance

I have Moodle 1.5.3 as mysql in the hosting server is 4.0(I use linux shared hosting) and my dream has been able to upgrade into 1.6 beta to enjoy new Moodle features. And today, I have many problems with my Moodle production site. And when I logged into the cpanel of my account, I found that mysql has been upgraded from 4.0.24 to 4.1.19. The problems I have experienced since 5 hours:

1. Formal_white template still works with color, however, the font is changed into Times New Roman.

2. I put the log in block in the frontpage, and when I enter username and password, nothing changes. However, if i refresh the Firefox browser, then I am logged in. The same procedure is needed if I want to turn on/off "Turn editor on".

3. Then I go to the Admin page by clicking on the Administration, then there is only Variables link occurs, others disappear. I tried to switch to all other templates, from Standard to Logo Standard templates, but none of them display font properly.

4. Then, I tried to browse my Moodle site with IE and in most of time, it can not be loaded.

So, I don't know what to do, I have some questions, please help me, Moodle experts:

1. What if I upgrade Moodle into 1.6 now? Will the issues be fixed?
2. What should I do to rescue my courses, quizzes and resources ?

Thank you, and I am awake to read your helps, tonight!

Dinh Lu Giang