I'm not up on which SRAM parts are compatible with Shimano, But you could get a new Shimano RDER for about $20-25?
I like the Shimano EF-65 shifter/brake combo, although the EF 51 will also work.
The 4 finger version is adjustable for V or Canti brakes.
IF you want to go to 9 speed, get 9 speed shifters, RDER, chain & cassette. Since you are changing some parts anyway, now would be a less expensive time to do it.
I like the much wider variety of cog combinations on 9 vs 8.