Yes you will need to keep seeding until someone else has finished downloading it from you and usually once a few people have finished and continue to seed then you should be able to stop.
My Computer
Computer Manufacturer/Model Number
Home Brew
OS
Windows 7 Ultimate Vista Ultimate x64
CPU
Core 2 Duo E8500 3.16Ghz @ 3.8Ghz
Motherboard
eVGA 750i FTW
Memory
2x2Gigs Patriot PC2-6400 LL
Graphics Card(s)
Inno3D GeForce GTX260 216 SP
Monitor(s) Displays
ASUS VW222U 22" 2ms Response time
Screen Resolution
1680x1050
Hard Drives
SATA 150GB
SATA II 250GB
USB IDE 750GB Ext.
PSU
HYTEC 600W & Thermaltake 650W Toughpower Power Exp
well i am upping something to the nova and the page to up the torrent to is just sitting there loading..as if its actually downloading the file from me..so thats why i wondered if i also had to have my client open too, cause it says no one is downloading from me.