numbers formatting error in reports

Hello All,

I have developed a custom report by reports builder then i created the RTF file and everything is okay

but i need the some field numbers format like this 9999,9999.00

my question is how to show the comma separator in numbers  as well as the decimal  ?? 

for example 

 1500         to be like this  1500.00

 982.2        to be like this    982.2

 98420.02  to be like         984,20.02

 Note that the format i want appears correctly in reports builder environment

 -attached file is the report output just for clarification-

Thanks