check the following function: Format Currency

Use it as: (123456789.12345).formatMoney(2, '.', ',');

I know you've found a solution to your question, I just wanted to recommend that maybe you look at the following more extensive jQuery plugin for International Number Formats:

International Number Formatter

maybe there is a better solution out there but off the top of my mind, remove the $ and comma then use parseFloat(YOUR_NUMBER)

check the following function: Format Currency

Use it as: (123456789.12345).formatMoney(2, '.', ',');