Can you put the vertical on top of your house with radials on the roof?
^This. It's what I'd do.
But also don't expect much from the antenna you have on 17m, it's a terrible 17m antenna. Should work okay on 20m, though.
A good multi-band (trapped) vertical with a good set of radials installed above your rooftop would likely outperform it almost all the time.
If you're severely blocked to the east (towards the mountains), you may not do so well in that direction, but there's still other directions!