Well you really need to show it to competent mechanic to advise you correctly whether you need new hose or thermostat or both. It looks only hose to me from the picture.
For the parts, leave it to the part center advise if its available as two pieces or one as many time our assumption doesnt match with part dealer greed here.
I have to buy 200 dhs gear shifter cable for 5 dhs plastic bush needed for my wife Trail Blazer.....!
Can we see a better view of leak and thermostat and some more detail about the car to advise properly?
Not all leak need thermostat change as may be it's installation done wrong. Thermostat usually don't leak but they fail to open and close at right time to interchange the cold and hot coolant.