I'm with Abarne, take more time to learn the airbrush you have. The 175 is a decent brush. The clogging issue you are having may have more to do with either not thinning it enough, or you're getting tip dry, a common problem with acrylic paints.
However, you will likely still have problems getting the 175 to do a very fine line. It's just not designed to be a fine line AB, and is meant more for the T-shirt market. Did you get one with the optional parts for fine spray (Part #41-033 Regulator, #41-81DT Needle & #41-003 paint tip)? That may help. The best option for fine lines is a gravity fed dual action like the Badger 100LG, Iwata HP-CS or Paasche Talon. The gravity fed design uses less psi which allows for finer lines to be laid down.
While Andy's suggestion of the 200NH is a good one, you'll probably find you get much the same results. That's because the 155, 175 & 200NH all share the same regulator and nozzle. IF you do want to get one to find out, check out the Badger Garage Sale (about halfway down the page). They have the 200NH listed at $22 which is an incredible deal. They are "blemished" airbrushes, but I bought a couple of ABs from them, and the blemish was the word "Demo" engraved into the side! Actually, they're still selling the 100 Side feed (available in LH for southpaws or RH for righties) which is a dual action gravity/siphon fed airbrush for $26. The side feed allows for the lesser air pressure which in turn is better for fine lines. It was designed as a photo retouching tool, and would be an excellent deal.
So excellent I may have to buy one to add to my collection. After all, I already have the 100LG, 150 siphon, 200-20 detail and the 100RH would fit right in!
If you can find a 200-20 detail brush with the fine needle and regulator/nozzle combo, you'll be better off. But my gut reaction is to tell you to practice, practice and practice!
Another choice would be the new Renegade Velocity, which Bear Air is selling for $84.