Looks like she was born near Ennis, County Clare, Ireland about 1821; married in Ireland and travelled to SA on the Prince Regent. The obituary says they arrived in SA about 1853; the Prince Regent arrived in 1852 (no Howards on passenger list) and 1854 (unable to find passenger list). John died in 1876, buried in Marrabel but no death record. They had at least 8 children, presumably some at least were born in SA however I can't find any birth records. Apparently it is not unusual for Catholics not to register births or deaths in South Australia during this period. They lived at Gumeracha, Light (near Kapunda) and Tothills Creek before moving to Oodla Wirra.
Can anyone else help with her maiden name?