any money she gives you would be a gift unless she is also put on the title (this should not be done unless you want her to be part owner)
if she makes a separate gift of $19K or less to each of you, she will not have to file a gift tax return. that is the money should go to each of you and then you turn around and use the gift to buy the property.
if she gives more, she'll have to file a gift tax return or if she makes a joint gift of $19K or more. it is unlikely she would have to pay any gift taxes unless she has used up her lifetime exemption - something north of $13 million. you do not report or pay income taxes on the gift.
