Programming prices in foreign currency

There is a page with the price list (see image in project). Normal php page, without a control system. Need to load once a day (17:00 GMT) exchange rates in dollars and euros from the Central Bank's website. Further training courses have already been taken to switch prices in the currency. It is important to consider:
1. Should be a link to the current version of prices, for example, switched to dollars, the link changed to "/?usd" . To give a direct reference rates in foreign currency.
2. If the course from the website of the Central Bank is not able to obtain, it is possible to use the old data and send an error message to the post office.
3. To save the decimal digits, for example 15 000r., $2 500, $560 and 121 etc.

The price in the currency should be rounded as follows:
1. to 10 dollars and euros – not rounded
2. than 10 dollars and euros – rounded off to multiple of 5 in a big way. Examples: 13 = 15, 208 = 210, 1031 = 1035 etc.

In the comments just write the price and means of communication (skype preferably).
Offers without prices are not considered. Payment for this project in rubles via Yandex.Money, the card of Tinkoff.