#Improt this funciton in your py file

from openerp.tools.amount_to_text_en import amount_to_text
amt = 13456
amount_in_word = amount_to_text(amt)

print "Amount in word ::::::::::",amount_in_word

Hope this will help you.

Regards, Anil

in your python file import the following line

from openerp.tools import amount_to_text_en

Then create a function convert in your class in the file

def convert(self, amount, cur):
    amt_en = amount_to_text_en.amount_to_text(amount, 'en', cur)
    return amt_en

Here arguents are amount(float), language and currency. If you want to change the format again, then you can use any of the string operations like replace to replace the string we get from the amount_to_text() function