I don't have a subscription to Ancestry.com, but I can look at their index. There is a Josephina[sic] Villareal, born about 1921 in Hidalgo Co, TX. Now, I do have access to Heritage Quest, but their index is by head of household only and there are 47 Villareal families in Hidalgo Co.
I suggest you post a new query, ask someone with a subscription to Ancestry.com if they will look up this Josephina. Probably your gal.
You say she died in South Houston, is that the city of Houston, or county of Houston? If it is the city that is Harris Co, TX, and you can try the Random Acts of Genealogical Kindness (RAOGK) site -- http://www.raogk.org/faq-requesters.htmhttp://www.raogk.org/faq-requesters.htm -- There are several volunteers listed for Harris Co, TX. Maybe one of them can look up the death record for Josephine/Josephina, and an obituary, if there is one.