Games : In-game ping went up after upgrading internet speed

I have a problem with my online In-game ping.

I had an ISP that gave me 3 Mbits/s and my ping was about 80 ms, then I changed my ISP and got more speed (5Mbit/s) but that made my ping went up, now I'm on 140 ms. What's the problem and how can I make my ping go down?

By the way, I'm using a new wifi router, could that be the problem? I didn't test it with an ethernet cable, because my computer is too far from the ISP modem. Help please!