"Now we have to create one in two weeks."
Translation:Ahora tenemos que crear uno en dos semanas.
I usually think of ya as meaning "already." That has a different connotation than "now."
Tener que = to have to do something, necesitar is more along the lines of needing something, I am pretty sure
You left out the "que" between tenemos and crear. "Have to" in Spanish is "tener que".
Why does 'una' work when the object is unspecified? I thought if unspecified, using the gender specific form was incorrect.