All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
The difference between Khimaar and Jilbaab is that the Khimaar is what a woman wears on her head and rolls it over her head and down and around her neck and chest in the presence of marriageable men. Allaah Says (what means): {… and to wrap [a portion of] their head covers over their chests.}[Quran 24:31]. As regards the Jilbaab, it refers to the dress that covers the whole body. Imaam Muslim reported that Um 'Atiyyah asked the Prophet : "Some amongst us [women] do not find a Jilbaab to wear? Thereupon the Prophet said: "She should borrow one from another sister." [Muslim]
We have already issued Fatwa 83702 about the description of the Hijab that a woman should wear when she goes out and when she is in the presence of marriageable men, so please refer to it.
As regards your question whether or not a woman should cover her feet with the Jilbaab, the answer is yes because the feet is an 'Awrah which a woman is obliged to cover in the presence of marriageable men. The evidence about this is that Um Salamah asked the Prophet : "What should women do with the lower end of their garment?" The Prophet replied: "They should extend it the length of a span of a hand." She said: "Their feet will thus be exposed?" Thereupon, the Prophet said: "So they should extend it the length of a cubit and should not extend it further than this." [At-Tirmithi and An-Nasaa'ee]
Allaah Knows best.