「今週」 (konshū) means "this week." You use it to refer to the current week you are in. It can be used with present or future tense verbs. For example, 「今週は忙しいです。」(Konshū wa isogashii desu.) means "I am busy this week."

今(いま)週(しゅう)は今(いま)の週(しゅう)。今(いま)週(しゅう)は忙(いそが)しいです。