I've been searching for this programme for years, not knowing what it was called, and have finally found the name of it. 'The Girl from Tomorrow' was a programme about a girl called Alana (from the year 3000). At the start of the series she's kidnapped by a criminal called Silverthorn and brought back to the year 1990. Here, she meets a girl called Jenny who helps Alana adapt to life in this time and eventually returns her to her own time. Alana had special powers and wore a head band type this across her forehead. An amazing programme.