A few words of advice from someone who has been self-employed for a long time.
First advertising is effective to the extent people knew about you before, unless you have very well-targeted advertising. When I started out, I spent a fair bit on advertising but the only thing that got me a return on investment was, believe, radio advertisement aimed at individuals and small businesses.
On the other hand my initial PR efforts made me a lot of initial customers.
First: Work on your presence
So before you start advertising yourself, you want to improve your presence generally. You get out of this (and the resulting advertisement) what you put into it. If radio stations offer a package for an interview and advertising (if you are trying to reach end users) this may be helpful. Talk to them. If you are involved in open source projects with reasonable profiles, work on making sure you are known there. For example I do a lot of PostgreSQL-related blogging because that drives traffic to LedgerSMB.org, and then when people start using that software, I am usually the first person they come to looking for support.
Next, how does your advertising fit into this?
Advertising, done well, is a way of supporting this presence-building effort. It is not the entire effort, or even the central aspect of it. It is instead how you build that last piece in. When I go to conventions I look carefully at the target audience, and I divide my advertising into three sections:
What will get people to stop and talk to me?
What can I give them when they do?
What can I given them beyond that which may drive business later?
For example when I went to the Malaysia Government Open Source Convention a couple years ago, I put a lot of effort into my marketing and it paid off. First I offered to make my booth available for marketing PostgreSQL as a database (and thus I got support from the PostgreSQL community including marketing material). Then I selected marketing material there specific to governmental use. Then I put together the LedgerSMB stuff that I figured I could give out separately if the chance arose. Unfortunately I made a critical error and so I missed the major target market but I did get significant interest and traction and I got two smaller gigs from peripheral markets.
So this material I would give away were the advertising materials. Some of which I prepared (glossy fliers) and some were prepared by others (success stories about the French government's use of PostgreSQL).
None of this would have worked if I was not reasonably well known in the PostgreSQL community. I thus basically took my presence and I build advertising around it.
Putting it all together
Classic, traditional advertising materials are relatively helpful once people know who you are, or once they get to meet you. Advertising thus works better for larger companies who already have brand recognition than it does smaller businesses.
In general, as a freelancer or consultant, one of the best things you can do is create original content which showcases your knowledge. You can then reference this in advertising materials and incorporate what you can do into them. Remember, you are not selling yourself so much as what you can do, and nothing shows what you can do like what you have done.
Your existing presence and reputation is the foundation on which you build your advertising. The advertising then further boosts the presence.
 The Malaysian Government wants to deal with Malaysian-owned businesses. I should have come in partnering with an existing local business already but instead I came in by myself.