Hey, i can tell you right off the bat that it is highly unlikely you will find bitcoin investors with the rate of return given, I know of many bitcoin investments that offer over 2% per week which is much higher, however I can give you a few reccomendations for your website. Firstly offer an English version of the website, this is very important if you plan on marketing internationally. Also note that there are alot of men who use bitcoin so perhaps have some products that appeal to men on the homepage if you want to sell to men. People who mine bitcoin might consider purchasing if you can offer products that appeal to them that they can pay for with bitcoin. However if a monthly fee is associated with offering bitcoin as a payment solution I would scrap that idea. If a small percentage of the sale is associated then go for it. Im not exactly sure what bitpay charges but check them out.