1. how long does it take for listings to rank better, whats the average amount of sales i gotta do in a month.
The algorithm is proprietary and quite often unpredictable but in my opinion account strength is #1 factor, followed by sell through rate. It's not just the amount you sell that's important; what % of listings sell is also crucial. It is also known that eBay favors new listings over re-listings.
2. Also, how can i drive in traffic to my ebay store?
Ranking is #1 factor, even more than price. People used to be able to game the listings to rank but that's gotten much more harder the last few years. My advice is if you're going to do this long term, do not take shortcuts, since eBay and Amazon tweak their algorithms all the time which wipe out the ranking tricks.