Currently using 205/45/17...i see this size very less, 215 more... Is it ok to use different size?

Sure, as long as keep within +-3% variance of the circumference.

Still can use 215/45/17 coz it's only about 1cm bigger in diameter.

205/45R17 is your original size?

No idea what's the original size, but the last tyre change and using now is 205/45/17...what size u all recommend for next change, if I can choose

Check the sticker by the center pillar on the driver side. This will tell you what is the original tyre size.
If you do not know, this 205/45R17 could already been "upsized". So now you ask the question can change other size, some will tell you to go for 215/45R17 which is more common.