I trust that you found Helen (as Hellen GALLAWAY - note the spellings, both of given and surname, when you search) in the 1841 census on FreeCEN at: http://www.freecen.org.uk/
Unfortunately, the 1841 does not give marital status or relationships, and ages of persons over 15 are rounded down to the nearest 5.
Helen's father, Lewis, may well have passed away before that census.
I did a free search on ScotlandsPeople for the death of an Ann GALLOWAY, other name DEWAR born 1800 +/- 10. There was only one. Refining the parameters revealed that this Ann died in Aberdour, Fife in 1888 aged 89. Very likely to be Helen's mother.
JAP
Logged
Scotland - HALL, HARLEY, LOCHTY/LOCHTIE/LOUGHTIE/LOUGHTY (very rare), MCLAUSE/MCLAWS/MCILHOSE/HOSE (quite rare and many very variable spellings - close to 100 to date), PHILP/PHILIP, VASSIE; Ireland - BOURKE/BURKE, DONOHUE (many spellings), DOOLEY, KINSELLA, MAXWELL, OSBORNE, RAFFERTY, STA(U)NTON, SULLIVAN; England - BAYES, BROWNELL, DALTON, FREEMAN, HACKING, PIERCY, SIDDLE, SWIFT, SULLIVAN, TINK(L)ER, TRIPPIT. Any spellings and many other names!