My laptop only charges when I wiggle the cord?

I've had a Lenovo Ideapad P400 Touch for about a year and a half. A few months ago it started having issues holding a charge for longer than about an hour. Just recently it's now even having trouble charging in the first place.

OS is Windows 8.1

I've updated the battery drivers from the Lenovo site.

I'm assuming the connection itself has worn down? My question is what should I do first? Take it into a repair shop? Buy a new battery?

The battery can only be removed by taking the whole thing apart so it's not exactly a simple task.

If I take it in for repair, how much is it likely to cost? Considering the price of the laptop, getting a new one isn't really an option unless the repair is extremely expensive.

Added (1). I've tried a new charger, makes no difference.

Why update drivers to fix a hardware problem? Not holding a charge normally indicates the battery is failing. That can 0ut extra load on the charger as it means it carries a lot of the load on ots own when the machine is running. But you could have a break in the cable or the connector inside the machine.