when you say your bmr is 1691 does that include your daily activities or is it your straight bmr nothing else? if you are confused www.sparkpeople.com/resource/calorie_calcu
this spells it out for you.
if that 1691 number does include your daily activities, then 1691-250 [250 is the calorie deficit you need per day to get to half a pound a week] =1441. so your ranges should be 1191-1541. that's if you do absolutely no exercise. keep in mind that when your math range numbers dip below 1200, that tends to mean that your goal is a little too aggressive unless you're quite short [well under 5' tall] or quite elderly. if you do exercise then you need to divide your weekly exercise by 7 and add that to both ends of your ranges. so if you burn 700 cals a week, you'd add 100 cals each day, making those numbers 1291-1641.
if the 1691 number doesn't include daily activities, then that means your bmr and daily activities are 2029. to lose half a pound a week, you'd still be aiming for a 250 cal a day deficit or between 1779-2129 cals. again, that's without exercise.