Kymco vitality 2T50 Scooter battery size.?

Right now my scooter has a 12V 3Ah battery and the electric starter doesn't work and the blinkers don't work right. My dad says I probably need more Ah.

What size do I need to get?

Thats the correct battery for that scooter, don't up it up..
The battery is probably a dud (a lot of stock batteries are crap), so you might want to replace it with a decent Yuasa brand battery.
Also, think about getting a Battery Tender Jr. to keep it fully charged.