Bonded 3m T1 ISP suggestions and experiences?

I’d like to get some feedback on this.

My company has roughly 100 users. We have 4 office, 2 of which are international in Dublin and Singapore. NY is the hub. Since I arrive here I’ve noticed considerable connectivity issues in the Dublin office and a general overall slowness on the network.

I’ve made a number of infrastructure improvements including upgrading several of the firewall units. I’ve relocated a couple applications to under utilized servers to reduce the congestion to heavily used file servers.

Although I have seen some improvement, it’s not what I was expecting. We currently have a single T1 line and I’m strongly considering upgrading to a full 3m bonded t1.

Does anyone have an recommendations?

Thanks