Conditional formatting

Hi,

I'm comparing data from two columns using "data bars".The problem is that what i see does not reflect the reallity,f.e. comparing 6 and 4 resulting in the same bar width as with 9 and 1.To solve this i'm seting the values myself,the shortest bar to 0 and the longest to 10 and it works fine that way.But it's almost impossible to do it manually with over 100 records.
Maybe i'm overlooking some simple option which could resolve this?

And the second thing that bothers me concerned data bars as well.Is there any option that could change the bars' colour based on the cell value?In above example if cell value is 1-4 then bar would turn red,5-7 blue and so on...Is it possible in excel 2007?

Any help will be greatly appreciated.