You likely don't need new amp at all. Your old Sony, unless malfunctioning is probably has much better amp than either amp choices.
Now I do get the dac part - PC's analog audio paths could be really bad (ie extra noises etc...)
You could just get an good and expensive dac like Behringer's UCA202 (just make sure to use it's line out ports, not headphones out)
But if you want something cool, a bit expensive, but cool:
https://emotiva.com/products/amplifiers/pres-and-pros/ta-100
This one might actually have better stuff