Your old isp had better routes through Dota servers. You can't actually say "I upgraded my internet speed by changing isp", because there are many factors that you should consider when saying that, one of them being speed to get [where].
You can double your download rate from [somewhere], while totally loosing connectivity towards [somewhere else] -> for example Dota servers.
When changing isp you need to consider your location, peering provided, what you use the most.
You asked: @JonathanDrapeau Any idea how can i low my ping without the help of the ISP?
Yes, you can, but requires a bit of knowledge. If you know a better route to your destination (Dota servers) you can set it manually (I presume you have windows so this may help https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/sag_tcpip_pro_addstaticroute.mspx?mfr=true - did not actually try it, I set my routes on my router). Also you can use a proxy or use tunneling software, but I recommend against it if you don't really know what you are doing.
One last edit...
140 is not such a bad ping unless you are playing in some high end games. For moderate games is pretty decent.
Yes, it may be your wireless too. Switching to eth would be better. And about the distance... come on, it takes you 10 min to make a cable, and that includes washing your hands after :).