Easy price update from currency Euro and $

i want this project for my oscommerce shop, we have allot of products and we need to update the price more easily, some price of products are in Euros or Dollar or our currency RON. We want to have on every product in admin in edit 3 currencies (RON, Euro, Dollar). If the product we buy from our distributor is 40 $ we will put in the $ section if the product we buy in euro will put in euro, and we want to transform and round this prices to apear on our shop in RON because we sell only in Romania. Example: if we put for product Hard Disk 80gb price 30$ on our site we want to apear the price in RON, ROUNDED XXX,00RON and not XXX,15RON. Sorry for my english and i think you understand this project. And we want the currecies to be updated by crontab every day. I forget to tell to be in admin edit product a button for VAT, in our country is 19%, the price will be calculated 30$ x currency + 19% = xx,xx ROUNDED = xx,00 RON if the button is selected, if not VAT needed will be calculated 30$ x currency = xx,xx ROUNDED xx,00 RON