Unfortunately, there is no crypto price calculator feature on Coinmetro, so this will need to be done by yourself manually.
You can find the prices that you bought cryptocurrencies for within your Coinmetro transaction history. You'll then need to enter these into an external average crypto price calculator, such as the Average Crypto Price Calculator by Leverage Trading.
You can find your Coinmetro Transaction History by following the steps in the following Help Centre article: How Can I Download or Export My Coinmetro Transaction History?