Morcos,
Hock Anne does not keep much variety, so you won't get airgun scopes there. The bug*3r is quite rude as well!
Chye Whatt Seng, Unit No-02-73, 5001, Golden Mile Complex, Beach Road is the place to go. Ph- 62983586, 62971969. Working hours- 9Am to 6PM. closed on Sat, Sun, public holidays.
You could look for a Bushnell Sportsman airgun rated scope there within your budget. Rest are expensive. Walther may not last on an airgun, but you may try them and give us your feedback- positive or negative!
Feel free to take my name (AI, Squash, India)- I meet them regularly (even if I may not be buying anything). You will get a discount because of this!
[edited - moderator but this issue is discussed in this thread http://indiansforguns.com/viewtopic.php?t=3812&start=0 ]