You mentioned liking the old republic, but how feel you about The Old Republic? Like, books tied into the universe set up by the video game Star Wars: The Old Republic?
The books set in this period are quite good:
1- The Old Republic: Fatal Alliance is set in the Cold War between the Republic and the Sith Empire. It's a fun standalone story that I enjoyed quite a bit.
2- The Old Republic: Deceived is, in a sense, a novelization of the "Deceived" video game trailer. It goes into a lot of detail. It's amazing and fast.
3- The Old Republic: Revan is an expansion of the story of Revan (protagonist of the Knights of the Old Republic video game). It ties the original KOTOR game into the new TOR game. It's a bit weird if you don't know much about KOTOR (it assumes you played the games, or are at least familiar with them).
I haven't read The Old Republic: Annihilation yet, but it looks fun
There's also Red Harvest, which is set in this ancient era, but is more of a horror novel. It is a prequel to "Death Troopers", a really enjoyable horror novel set in the movie era.
Also, I recommend comics. Check out the various "Omnibus" comics, which collect a lot of material. Almost every single comic tied into the prequel era has been collected in the Omnibus line. Look for:
1- Omnibus: Rise of the Sith and Omnibus: Emissaries and Assassins, which tie into Episode I
2- Omnibus: Menace Revealed and Omnibus: Quinlan Vos-Jedi in Darkness both lead into Episode II
3- Omnibus: Clone Wars (3 volumes) collect a lot of the old depictions of the Clone Wars (before the TV series came out).
These books are all really good. Other stand-out ones include:
4- Omnibus: Tales of the Jedi (2 volumes), which tells of ancient wars between Jedi and Sith
5- Omnibus: X-Wing Rogue Squadron (3 volumes), which tells of cool starfighter battles post-Episode VI
6- Omnibus: Boba Fett should be self-explanatory.
Really, just explore your local comic book store and find anything labeled "Omnibus". Dark Horse Comics has published like 2 dozen omnibuses for Star Wars, and many more for their other lines (7 for Buffy, a few for Indiania Jones, Predator, Aliens, etc.)