I found these two census records for a Jane Anderson
Record Type Census 1841 Abstracts
Record Date 1841
Name Jane ANDERSON
Age 28
Marital Status Married
Relationship in Household Wife
Occupation
Townland Braniel
Parish Knockbreda
County Down
Record Type Census 1851 Abstracts
Record Date 1851
Name Jane ANDERSON
Age na
Marital Status Married
Relationship in Household Wife
Occupation
Townland Lessans
Parish Saintfield
County Down
There is also this record at the same address for a 10 year old John Anderson.
Record Type Census 1851 Abstracts
Record Date 1851
Name John ANDERSON
Age 10
Relationship in Household Son
Occupation
Townland Lessans
Parish Saintfield
County Down
Not sure if this is your ancestors.
I have never heard of New Bridge in County Down but found this :
New Bridge Clonduff 29: 23/29 over river Bann ;3km E of Hilltown on Spelga Pass road.
found at RosDavies website
(
http://freepages.genealogy.rootsweb.com/~rosdavies/)
Good luck
OTTO