I'm sorry to inform you, but you're not being paranoid. There are known al-qaeda agents in that area of the Dallas-Ft. Worth metroplex (Arlington and nearby). The people in the Plano-Richardson area have things a bit better; the mosque there (and the associated Holy Land Foundation "charity") just have ties to the Hamas and Hezballah terrorist organizations.
Unfortunately, you're not going to be able to do anything about it. Your local FBI office has some serious issues with the problem due to their own status of being compromised (at least one muslim agent who refused to accurately report back or allow himself to "spy" on fellow Muslims), as well as the large political clout the Moslem "religious community" has in that area (especially with the federal government, but even the local Dallas government was willing to use tax dollars to build the Richardson Mosque a new parking lot, excused because it could also be used as a DART park-and-ride facility).
Oh, and if you happen to see those clear plastic boxes in various delis, restaurants, etc. in your area asking for charitable donations, don't put your change in them. That money is funnelled to Palestinian terrorists.