hey hummer
SEO/SEM are very generic terms now being thrown around by every web designer/marketing firm out there.
I could talk your ear off about this but to give you a general summary:
1) Increasing your online exposure takes work, including: content creation and distribution, website optimization and strategic thinking. Depending on your goals, you could just buy adwords, but are better suited to take a multi-prong approach that includes beefing up your website, creating a content stream (blog post,articles, social media channels) and sticking to them.
2) some changes are quick and painless, for instance, identifying keywords you want to rank for and re-inforcing your site with them, setting up a google analytics account/webmaster tools profile (this is a very quick way to get a better ranking) submitting sitemap,etc.
3) some are tough, depending on how crowded the space online is for your company/keywords, you could be looking at setting up a simple blog with a post every month, or setting up multiple websites and deals with other sources to get your content distributed and viewed. there are some grey area's here you can use to get to #1 or #2 for a search result, but it takes time
4) yes adwords is EASY, BUT , google will charge you based on your websites rank, so if youve got a crappy rank on search, you're going to pay a premium, thats why all the organic changes are recommended first, and then afterwards you can pay google to put your site up top on page 1 (and pay for the pleasure)
I could really talk your ear off, and while i dont specialize in seo, i create digital businesses for a living so i have alot of experience with this.
feel free to PM me, happy to give you a rough plan on what you should do but need to understand your goals better!