1992 Buick Lesabre Car sputters when accelerating

Before my 180 mile journey back to college, I stopped to fuel up. I normally use medium grade fuel, but decided to use high grade (in hopes of better performance). About a half hour into my 3 hour trip I noticed that my car wouldnt accelerate like it normally does. Then about an hour into my trip the acceleration started to get really bad. Whenever I would press on the gas peddle it felt like the car would bog down because it wasnt getting any fuel. I had to go up a big mountain and my acceleration was so bad that I could only do 40mph in a 55mph speed limit zone. The car was sputtering and struggling really bad to get power. I found a local garage on my gps so I took it there becuase I was afraid I couldnt make it the rest of the way to school. It took a couple times to get it started, then they did a fuel pressure test and said the pressure was bad. So they replaced the fuel filter which was very dirty. That seemed to fix the problem so I paid $84 for the part and labor and continued on my way. The car ran great for about 10 minutes then the problem started all over again. It got so bad that I couldnt drive the speed limit, so I had to pull over to let vehicles pass me. Please help!