Based on your current configuratio, which is:
dev/sda1 ntfs Label-Service002 16.67Gb
dev/sda2 ntfs Label-Vista 449Gb Boot
I would suggest, using SystemRescueCD, that you leave sda1 alone, this looks like your Windows recovery partition which you will need if your Windows system crashes and needs to be reinstalled. sda2 could be resized to something like 30gb, only you will know how much space you will need to Windows use. The actual operating system uses a lot less than 10gb. The remain space can be partitioned as per pags suggestion. You might want to consider whether you want your data to be stored on an NTFS partition so it is accessible from both Linux & Windows, in that case you need to either create a separate partition for this or use a larger Windows partition. I hope that isn't too confusing.
Before performing any operations backup any data on your machine to a flash drive, remove an unwanted files & software and check if you need to do a defrag.
You can setup all your partitions and perform formatting on all new Linux partitions using the SystemRescueCD tool, so when you come to doing the actual install you can select "use existing partitions" option. I find this method safer, although I would suggest writing everything on paper so there is less chance of a mistake.
Remember you don't need to format sda1 or ads2, these are Windows partitions and will not be touched during the Linux install.