ןIf the house I live in is on a hill above the street level (there are steps to climb to the front door) can I still light at my window? Does the height requirement begin at street level or at my house? People walking by would still be able to see the menorah in the window easily and it catches the observers attention.
In principles, the height is calculated from the public thoroughfare, meaning the lower street level, and not from your private yard/staircase (see Yemei Chanukah, p. 101, citing from Rav Nissim Karelitz; Teshuvos Vehanhagos 3:215).
However, if you share the higher level with others, there will at least be a pirsum le-rabim for those who share the higher level with you.
It is therefore best to light within twenty amos of the street level.
If this is not possible, it is possible that you should still light in the window, which is preferable to lighting at home, because as you note, people will in practice note the candles at the window (see Shevet Halevi 4:65).
Note, however, that a number of poskim write that when the window is above 20 amos, it is preferable to light inside by the door, thereby gaining the virtue of lighting within 10 tefachim (see Shaar Hatzion 671:42; see, however, Peri Megadim, M.Z. 671:5, and E.A. 6).
Yet, if there will be a degree of pirsum to members of the public domain, there remains room to prefer lighting at the window.