The most likely thing to do, I think, is to replace (change the value) of c11, a 560 pF capacitor, that is wired to the toggle switch, that is your band switch. I believe with the 560 pF capacitor switched in the circuit, to parallel it to c1 (the 365 pF variable tuning capacitor) you are on the higher frequency band, and when c11 is not in parallel with c1, you are tuning the lower frequency band. (I hope my logic isn't reversed here.)
I also found that increasing the battery voltage from 9 to 15 volts, the tuning ranges changed noticeably on both bands. That might be another option to experiment with. (15 volts also gives much higher audio to the speaker.)
How is your regeneration control doing? Mine was very unstable on both bands until I inserted a 10 ohm resistor in series with the one turn (feedback) loop that goes to the center of the torroid coil ring. (I've built a number of regenerative receivers before, so am familiar with good ones and unstable ones.) I connected the resistor to the one turn loop, on the side that was outside the center of the torroid coil. That vastly improved the stability of the regeneration control. Encouraged by this, I will fine tune the resistor value to see if I can get even smoother regeneration. (Greater that 10 ohms, and I lose all regeneration, but I might get better stability with, say 8 ohms. I will have to try this.)
How does the performance on the two bands of your receiver compare? Mine is now very stable and useable for cw and ssb on 80 meters, but no luck yet on the top band, for 40 meters.
Hope this helps you out.
... Jerry Wysocki, KC9JXE