You're in Richardson? I believe Verizon FIOS is available there. DSL/Cable would be better, faster and more reliable than your existing service via the card.
I would not recommend using someone else's service regardless if you're ethical about it or not. Assuming you're not a sec guru... Assuming you do your best to not do stupid things on your network/Internet connection - you can't control/assume your Internet connection partner will do the same. Also, if your stuff gets comprimised you could comprimise or otherwise infect/cause issues with their stuff. Which would make the neighbor relationship decline.
My '03 Sold.