I'm going to take a wild guess here that you're building a clock of some sort, since you mentioned 30 LEDs and 7-segment displays (4 digits plus a colon comes out to 30 LEDs).
If that's the case, then the LEDs are used for indication rather than for illumination, so you can probably get away with running them with very little current. Run some experiments to see how low you can go while still being visible in whatever conditions it'll be used in. You might be able to drop them to 0.25 mA or lower, which would increase the run time to 20 days (and maybe a month or more since the current draw will be even lower at night). And assuming this is a clock, not all segments will be lit simultaneously; in fact, only about 2/3 will be lit at the same time, on average. So the average current consumption will be slightly lower than with all 30 LEDs lit all the time.
If 0.25 mA isn't enough to make the LEDs bright enough, perhaps you could add a dimming/undimming feature (e.g., push a button to show the time, then dim again after a few seconds).