you can also use 앞두다 = to have smth ahead (naver it for more info) for example: 선거를 2주 앞두고 한 후보가 사퇴했다 = With the election two weeks ahead, one of the candidates resigned 그는 그의 내각이 의회에 승인을 한달 앞둔 상태입니다 = He now has one month to present his cabinet to parliament for approval therefore, in one week = 1주일 앞두고... in three months = 석 달 앞두고...

As Mojave said, "in a week" is could read differently according to another context just like English.

There are a couple different ways to say it (depending on future or past events, I think). Check out: http://dic.daum.net/search.do?q=in%20one%20week&dic=eng