There are a few different options when it comes to brightening up your humbuckers. The most important thing is to try out each and see which one gives you the best possible balance for your sound.
Change the tone pots to 500k or 1 meg to get a brighter sound.
Swap your Alnico magnets for Alnico V magnets to brighten the tone.
Use a single-coil pickup that uses a humbucker casing.
Don't forget about using humbucker-sized pickup rings.
Also, use coil-splits to monitor the push and pull tone pots.