First off: you CAN do it. I've managed to do it twice (for a little bit more than a year with both). That being said, I cannot honestly say that I enjoyed it. However, I reminded myself every few hours that I made a commitment to do it. Somehow that made pumping easier for me - particularly when I was at work.
My second was born prematurely, so I followed the NICU nurses' recommendations to pump initially. Hence, I pumped at least every 2 hours around the clock for the first 2 weeks. Fun? No. Milk? God, yes. In retrospect, that was the best thing I did. Even once my son started to nurse at about 2 weeks, I kept pumping like a nut (6 times a day) d/t to oversupply from all that previous pumping. By the time I went back to work when he was 3.5 months, we had 9 cubic feet of frozen breastmilk. Takes a ton of effort up front, but you'll also get a ton of milk. I ended up donating to our local milk bank, since I had about 24 oz. extra each day. When away from him, I pumped at 5 AM, 8-9 AM, 11 AM, 2 PM, 5 PM, and 9-10 PM (and sometimes more).
If you can, I'd avoid supplementing. Every time you do, you're telling your body that you don't need to make milk then. That being said, some breastmilk is better than nothing, so I wouldn't feel guilt about mixing whatever you get w/formula if it comes to that.
Also, buy/rent a hospital-grade, double-breast pump. I used the hospital's while I was there w/my second son and then switched to a Medela Pump in Style once home. I can definitely tell that the motor is going on mine after multiple years of pumping between my kids. If you think the motor is dying on your old pump, I'd probably invest in a new one. Even if you don't get a new one, I'd replace the old parts (valves, flanges, etc.).
Is your significant other supportive? I told my hubby that this was my priority, and he stepped up to facilitate that. If your significant other doesn't think BF is a big deal, it's a whole heck of lot more difficult. I'd find a friend to commiserate with too. (I lucked out at work, and due to a baby boom in my department, 8 women were pumping with me. Misery loves company.) La Leche League might have a group in your area?