Is this your first half marathon?
My "standard" year around running schedule is 6 miles twice a week(tuesday and thursday), plus a long run on Saturday. So I might do something like a 6 miles run one week before the race, a 5 miles run (tuesday for me) and then a 4 mile run (thursday for me). Is your race on sunday?
Of course, the milage depends on what your used to running during your training phase. I think the key (at least for me) is to taper your milage down to the point where you feel like your body can really recover and strenghten itself so that on race day you have the energy and power to complete the race as strong as possible.
I'm doing a full marathon on the 16th of this month, and will probably not run more that 4 miles a couple times the week before the race.
Just remember, if you followed a training schedule your body is already "trained" for the race. For me, the most important thing the week before a race is fueling your body with the proper nutrition. Really concentrate on making smart nutrition choices(as problem area for me).
I'm not an expert by any means when it comes to running, this is just what works for me.