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I don't know what title tag to use.  Would take more KW research than I am able to do at this time. The post pages are not being found because your content management system is inserting a bad link.  It can probably be fixed by working the code in your template page. This site has some good rankings even though there is a lot wrong with it.  If you are getting some good traffic and making a few sales it would definitely be worth the money to hire someone to fix the technical problems. There is also a lot of potential to improve your conversion rate. Good luck with it.

Google's crawl rate varies based on many factors. For example, the New York Times website (nyt.com) probably has it's home page and category pages crawled a few times each day. A website such as yours which has static content, offers few links and has low DA may require a few weeks to be fully crawled. You can check Google's cache date for your pages on any search result page. Near most results you will see the word "cached". Click the cached link and you will see a header which offers a date/time stamp of when the cache was updated.