The Jewish community here is small and tight-knit. There are shuls for all denominations - Orthodox/modern orthodox, Conservative, several Reform, even a Reconstructionist rabbi at one time - and a fair amount of cooperation between denominations. read more
The JCC houses several synagogues and serves as a meeting place for community events. There is even an annual Jewish Film Festival in Austin. Members of the community come from all over. read more
The community definitely isn't wholly gathered in any single area. The Far West (Northwest Hills) neighborhood mentioned is indeed the best bet for something like that. The Jewish Community Center is located there, and with that (and nearby) a couple of synagogues representing several different congregations. read more