Cisco ISR 2901 - Should I add expansion modules, or upgrade to new router?

We are a non-profit with around 60 users on-site, 10 in remote offices, and 20 VMs.

Currently, it is five Cisco 2960s, an ASA, and an ISR 2901K router all plugged into another Cisco 2960 switch which we call the core. It is 100% 1Gb and no LAGs.

it’s actually working pretty well and is very stable but could be a little faster.

My first thought is that we coukd get a router with 8 or more ports to be the core which would eliminate hops. The 2901 has expansion slots so that’s an option as well.

We don’t have a lot of discretionary money to throw around.

Thoughts?