If you usually get Redback, you can try Cupping Room in Wanchai for roasted coffee, starting from HK$150/200g. The roaster is Sweet Bloom Coffee Roaster from Colorado. The bean should be fresh enough, mostly 1 week post roast.
The Cupping Room Wan Chai
https://www.facebook.com/Cuppingroomwanchai
32 Swatow Street, Wan Chai, Tel: 2371 2338
Not quite Causeway Bay but further to Happy Valley, you can get the renowned Intelligentsia of Chicago at Cucus, the coffee is around 1 week old post roast or fresher, depending on how you coordinate with the shop. Some might say it's quite pricey at HK$300/12 oz but quite a few of locally roasted coffee can be had for more $$$ than this. Plus it's a hassle to contact Intelli direct in the US for retail purchase which could end up in similar pricing or more.
Cucus
https://www.facebook.com/cucushk
8 Cheong Ming Street, Happy Valley. Tel: 28127223
Locally roasted coffee you can get 18 Grams at City Super in Time Squares or its own shop near Fook Lam Moon in Admiralty/Wan Chai. Pricing should be around the Cupping Room level or slightly less expensive. 18 Grams started out by Aussies and, to me, it maintains that style well since its start; it should be similar to Redback. Or you can try Coco Espresso which locates quite close to Three Pacific Place in Admiralty/Wan Chai area. The roaster at Coco went to Sydney, Australia to learn about coffee back in early 2000 and is among one of the pioneers for indy cafes in HK since 2007, I think.