Technical SEO Question about TLD combined with SubDomain

[Socialdude]

I am making a new website but need to figure out the best way to do this in terms of SEO.

I would like the website to have functionality of brochure website combined with an online store.

My issue is that I will be using software called prestashop for my online store and CMS called MODx to develop my brochure site. (These can not be combined into one CMS).

I can create brochure site with MOdx = www.example.com & then from that a subdomain using prestashop for my online store = store.example.com

Can I get Google to index these as one site or would I be better off trying to get everything under the TLD.

Ideally I would like just one site without subdomain

Bacially what I am asking is...

What are the effects of having subdomains in terms of SEO?

Am I better of having everyhitng under TLD?

Can I get Google to view TLD and Sub as one site?

Hope this makes sense, thank you.

[AlanMosley]

There is no evidence i have seen that shows a subdomain acts any different to a subfolder. Rather the opppersite
http://www.mattcutts.com/blog/subdomains-and-subdirectories/
http://googlewebmastercentral.blogspot.com/2008/01/feeling-lucky-at-pubcon.html

by the way, a TDL, referes to the .com in your example, root domain is example.com and subdomain store.example.com