+1 for Health Cabin . I usually get my shipment in 3 to 6 days ( but I am in Sydney , where they land , so no delay with interstate postage) .
Yes , you certainly can refill your cartos , some of mine have lasted as long as a month .
As for a good tobacco flavour , it is basically impossible to replicate the taste of burning vegetable matter , also , with over 4000 elements in typical cigarette smoke , no one in their right mind would even try. There are some very pleasant tobacco juices out there , I am doing a lot of experimenting at present , and , for the most part am pretty happy with the results .

With the exception of Nicotine liquid , if you need supplies , support the Aussie vendors. Typically , they carry everything that the overseas sites have , shipping is faster and cheaper , also , many will have a phone number that you can call should a problem arise.