The best I can do is give you some names and addresses, but, like cdjack, the ones I go to are all inside the Loop or in Spring. Maybe you can make it to one of them:
Yarns 2 Ewe (probably the closest one to Hobby, at about 12-14 miles away, which also has a GREAT selection--my usual shop)
518 Shepherd Drive
Houston, TX 77007
Mary Charles Yarn (Small but nice selection, not far from Yarns 2 Ewe--also about 12-14 miles away)
1710 Sunset Boulevard
Houston, Texas 77005
Nimblefingers (Needlepoint and Knitting, but small selection and farther out--25 miles or so)
12456 Memorial Dr
Houston, TX 77024
Twisted Yarns (this one is REALLY far, but great--about 35 miles away)
702 Spring Cypress Drive
Spring, TX 77373
I would recommend plugging them into Yahoo! maps and seeing if any of them are in your range. There are a few others, Merribee Needlearts, The Hen House, Upstairs Studio, and Yarntopia, but I've never been to them, although The Hen House, Upstairs Studio and Yarntopia are REALLY far out (Spring, La Porte and Katy, respectively), and I haven't heard many good things about Merribee (although if someone HAS been there and disagrees, please let me know--this is just hearsay on my part).
Hope that helps!