Older sound cards used to have two inputs, one for mic level (which is super low) and one for line level which is what is normally used to exchange signals between and within mains powered gear. More modern "chip on the motherboard" interfaces don't have a spare socket but a few let you do a software adjustment to make the single input suitable for mic or line level--even this is fairly rare these days though.
I don't know if your interface has such an adjustment--if it does, it would likely be on the Windows audio control panel. Don't be surprised if it's not there though. And, even if you have such an adjustment I doubt it would do what you need, unless your high levels are something like 50 to 100 times too high.
Sorry to harp on, but the real solution is to spend $60 on a proper USB interface. The stuff built into computers is simply not designed for proper recording.
