I was started pool mining with my GPU, is there any known issue/effect on mining with 2mb DSL bandwidth, i have a nvidia GF 640.
Your video card is whats impacting your profitability, not your network. A 640 probably isnt going to be profitable for much of anything out there. If you use NiceHash as an example, the lowest comparable card I see on their list is a 650 TI (more powerful than your card) and it currently makes 17 cents a day, before you pay 25 - 50 cents to run your PC all day.