custom graph problem

Hi,

I am monitoring a size of a file and have created custom graph.
NCV value is "data file size: 4500" which is 4500 MB. On graph I have
mentioned Y axis as size (MB).

Graph is working fine. But Y axis is coming like 4.0 k, 4.1 k, 4.2 k etc.
which is not looking good. How do I change the Y axis to full value instead
of "k"

Or is there any good idea where I can create graph of file size which has
no limit.
Here the condition is not like disk graph where we know the limit of disk
so we can set it in percentage.