Regex Pattern Money

I am a MyBB user. I want to ask, what if I want to write a nominal in a Regex Pattern

if the writing will be

2000 -> Rp. 2.000,00
20000 -> Rp. 20.000,00
200000 -> Rp. 200.000,00
2000000 -> Rp. 2.000.000,00
20000000 -> Rp. 20.000.000,00
200000000 -> Rp. 200.000.000,00
etc

please help me to solved this regex :)