Talk to me about Vitamins!

I take a multi-vitamin twice a day...my question is the vitamin B12....how often should I take it...I thought I was told to take it once a week but I looked on the bottle and the directions are to take it once a day.  What does everyone do about vitamins? I am especially interested in the B12. I had gastric bypass surgery this year in July. Does anyone take calcium too?

Multi            yes, two per day
B12 daily and shot every two weeks
Calcium    1500 mgs of UpCalD
3000 mcg of Biotin
120 grams protein supplemented

any others?

I take Citracal with D  2 in the am along with a sublinguel B-12 under the tongue every day ....At lunch I take a multi vit Walmart brand ( 2 of them ) and then at night right before bed , I take 2 more Citracal calcium.    You have to take the calcium about 5 hours apart from you multi that has the iron in it .  My Dr says that Citracal D is THE ONLY ONE that binds and that we really absorb..   I use the 2500 B-12 ..You pee our what you dont need .
I am 5 years our and my labs are perfect.   I have used this regime since 3 months out after RNY and never had a problem ,,,  Works great for me ..
Shirley