Being honest man, I doubt you are eating that few cals. Make sure to count every piece of food or drink all day long, including fruit juice/soda/snacks. Most people underestimate their intake.
Also, if you are currently not training at all, you might not need to decrease. Increased caloric expenditure from working out may do the trick for a while. Adjust calories once progress stalls.
As far as weightlifting, the number of reps is somewhat personal preference but depends on exercise. Low rep sets are Bench, Squat, Overhead Press and Deadlift (I like 3-5 reps). Next range up is dumbbell movements, chins/pullups, and back exercises typically anywhere between 6-10 reps. I wouldn't worry about anything higher rep than that.
There are many ways to progress. The most basic is probably increasing reps each week until you hit the top of your desired rep range, then increase weight. For example, once you can bench 135 for 5 reps, bump up to 145 and stick with that until you can bang out 5.
There are lots of programs on this site. Pick any one that has you squatting, bench pressing, overhead pressing and deadlifting each once a week and you should be ok.