Can I expect to make good money from my business?

As I've mentioned before I sell both an eBay auction sniper software I've been selling for over 7 years as well as a web based sniping service which I started last year. The first few years sales were very good and where I'd like them to still be today which is far from the case.

In the past several years my sales have fallen to a quarter of what they used to be. Before 90% of my sales came from eBay, now eBay sales fell so much that 75% of my sales now come from my website, and it's not that my website sales increased much, it's because my eBay sales fell dramatically, yet there's not much more, if not even less competition than before.

I'm having a new website done which should be online in a week and then I'll focus on SEO.

My question is can I expect to quadruple my sales back to where they were with a new modern website and good SEO? I also have the new web based version I didn't have back when my sales were good which has potential for good revenue since people must pay continuous (but minimal) fees to use it.

I personally think my business has great potential with a proper website and SEO. I currently rank high and even number one for terms fairly specific to my software like "best auto bidder" but for more generic terms like "ebay auction sniper" I'm on page 5-10. If I can get on page 1 for the more generic terms like "auction sniper" can I expect a significant increase in sales?

Thanks