EXCEL Conditional Format VBA - Colors & Fonts

Hello everyone. First of all, thanks a lot for your help and input.

I have been looking all over the web to find the code for the following (i am a newbee)

http://img51.imageshack.us/img51/9670/captureeu.jpg

(Conditional Formatting VBA to change the color of rows within a range if values in one column matches conditions given)

Above, I uploaded a screen capture of a simpler version of the the excelsheet im working on.

In the sheet I have linked A5 = C3, and from A5 to A22, I subtract increments of 0.5 from the cell above (So in other words A6 = A5 - 0.5) so when I write the macro those links got broken. So I gave up. I am trying to write a macro that will execute itself everytime I change the value in any of the three cells C1, C2 or C3 ..OR change the incremented value on column A explained above.

So lets say x = Value of Cell in Column A of the Range("A5:D22") for each row in the Range.
I want the macro to do the following
If Range("C3") >= x >= Range("C2") Then Color the corresponding row.Interior in the Range Gray
If Range("C2") > x > Range("C1") Then Color the corresponding row.Interior in the Range Blue and Font BOLD
For anything Else, Color the corresponding row.Interior in the Range Green and Font BOLD

This is the simple version with only 3 conditions, but my original .xls is much larger so I cant use Excel's conditional formatting feature:(

I really appreciate your help, thank you very much.