Perhaps you have all this info...
Marriage
14504/1913
HILTON John H
NELSON Emma R B
District Wagga Wagga
This certificate would give you Emma's parents' names and her place of birth. You can purchase a transcription of the certificate from a transcription agent for about $18 and the transcript is emailed.
http://www.bdm.nsw.gov.au/familyHistory/howToTraceYouFamTree.htm#TranscriptionAgentJohn's WW1 digitised service record is on
http://www.naa.gov.au/collection/recordsearch/index.aspxNSW online birth regs are only available to 1910. Some chatters have resources for births to 1918, and may help you.
Australian Electoral Roll
1930
HILTON Emma Rebecca 108 Union Street Erskineville HD
HILTON John Henry 108 Union Street, Erskineville Labourer
1933
HILTON Emma Rebecca 69 Wellington Street Newtown HD
HILTON John Henry 69 Wellington Street, Newtown Labourer
1936
HILTON Emma Rebecca 11 Trade Street, Newtown HD
HILTON John Henry 11 Trade Street, Newtown Labourer
HILTON Leslie Colen 11 Trade Street, Newtown Labourer
1943
HILTON Agnes Doreen 11 Trade Street, Newtown HD
HILTON Allan Henry 11 Trade Street, Newtown Labourer
HILTON Alma May 11 Trade Street, Newtown Factory hand
HILTON Emma Rebecca 11 Trade Street, Newtown HD
HILTON John Alford 11 Trade Street, Newtown Labourer
HILTON John Henry 11 Trade Street, Newtown Labourer
1949
HILTON Agnes Doreen 11 Trade Street, Newtown HD
HILTON Allan Henry 11 Trade Street, Newtown Labourer
HILTON Alma May 11 Trade Street, Newtown Factory hand
HILTON Cecil Roy 11 Trade Street, Newtown Motor driver
HILTON Emma Rebecca 11 Trade Street, Newtown HD
HILTON John Alfred 11 Trade Street, Newtown Mendler
HILTON John Henry 11 Trade Street, Newtown Labourer
HILTON William Thomas 11 Trade Street, Newtown Aircraft worker
1954
HILTON Emma Rebecca 11 Trade Street, Newtown HD
HILTON John Henry 11 Trade Street, Newtown Labourer
HILTON Shirley Isabel 11 Trade Street, Newtown Clerk
You can search for the marriages on
http://www.bdm.nsw.gov.au/cgi-bin/Index/IndexingOrder.cgi/search?event=birthsA number of their children served in WW2 and the service summaries give you their dates and places of birth.
http://www.ww2roll.gov.au/script/name.asp#searchtabsThis could be your John Henry's death
35127/1960
HILTON John Henry
Father John Mother Unknown
District Newtown
and possibly his birth
28102/1889
HILTON John H C
Father John Mother Mary J
District Wagga Wagga
You can search here for death notices...quite a few of the family names here including one for an Emma in 1973...died in Southport Hospital so death not on NSW death index.
http://www.ryersonindex.org/ However all this aside, you need the marriage cert to find Emma's parents and her place of birth.
Cheers
Cando