Hi Sandy!
A really good mexican restaurant is Rosa Mexicano on 58th and 1st ave and theres another on 18th street between Park and Broadway i believe. A bit pricey but pretty good and DELICIOUS pomegranate margaritas. Theres another called Dos Caminos on Park Ave, cant remember the cross streets. its similar to Rosa and their margarita specialty is prickly pear margarita and amazing guacamole.
On 16th st and 8th ave a place called Maryannes which is pretty good.
Theres another place called Mercadito which is really good. Cant remember where it is but it is in the village. Im sure you can google all of these, most have websites
Italian theres a place called Portobello, my fave Italian place in the city. Its in the west village on Thompson street.
Chinese on 60th and 3rd theres China Fun but its not a place to go out to dinner like for a night out. more of an early meal type of place but really good....
And aside from that there are a lot of good variety of places to eat. Its so many hard for me to remember all.
Lucy Latin Kitchen and Pipa are owned by the same people and are all in the 14th st.vicinity. Lucy Latin Kitchen is more carribean and south american food. Croquetas and empanadas are omg amazing! And delish mojitos. Pipa is more Spaniard and equally mouth watering. As you can tell i like alcohol lol so i suggest trying a drink in both
HAVE FUN. theres so much to do here and its summer thats so fantastic. not much beats NYC in the summer. but its hot so wear comfy flip flops and cool clothes. if you take the subway its HOT down there so just warning you. Go get some gelato down in the west village too. not sure of exact places but you can ask around. most are good.
if you need suggestions as to where to go out out let me know, although not sure if your sis would be down