First of all you should calculate your ROI in BTC, not in USD (since your income is in BTC) - so your investment is 0.9 BTC (June 7th BTC/USD price).

With the information you gave us, it is possible to calculate your ROI, because almost all variables are known (though still they are not constant). Since you started - the Bitcoin mining difficulty increased only once in your 17 days of mining, from 678,760,110,082 to 711,697,198,174 - thats increase by 4.63% and your profit dropped 7.97% (in 2 weeks time span).

Analizing my own investments in cloud mining I can asume that 5% increase in difficulty gives 9% decrease in profit.

The bitcoin difficulty increases every 2 weeks, so using simple math your initial investment should return in 280 days (9.5 months).