First off, if you want advice on being a cleric, the Cleric Handbook is the best place for it. Most of the guides on that site are actually pretty good, if a little in depth.
In 3.5, the default martial arts character is usually the Monk. They tend to come from monasteries, and the typical image of them is guy who spends several hours a day meditating, and several hours kicking butt. However, I'm glad you went with cleric, given that the monk is, mechanically, the worst class in core D&D. If your group suggests Monk, they probably don't understand how bad the Monk is.
You say you've already created a character—I'm going to pretend you haven't, or that your DM is okay with you rearranging your character. (It's often allowed to rebuild your character if you don't like them after the first session, rather than lump you with this guy for the rest of the game.) If your group says you can't do this, then build your way towards what I describe, but you might argue your case a little. Early rebuilding is an entirely reasonable thing to do, especially for a first time player.
Stats-wise, you're looking for high strength and high wisdom. Strength helps your grappling directly, and wisdom is what fuels your spellcasting. Even if spellcasting isn't the main thing you're looking for, just trust me on this. You'll want to have it. Maybe story-wise it's part of your legendary kung-fu stances. Typically, cleric spells are described as prayers to your god, so this probably is in line with what you wanted anyway.
Speaking of gods, you'll want to pick one of those. I don't actually remember the standard 3.5 gods, and I don't know if your group is using them either. My group typically makes them up as part of the first session. The main thing that differentiates gods is their Alignment (are they good, evil, lawful, or chaotic?) their fluff (that is, the stories about them and their attitude) and their domains. A domain is an area of existence the god has purview over—Zeus is a weather god, Mars is a war god, Loki is about trickery, etc. Each god in D&D has multiple domains, and each cleric chooses two from those under the purview of their god. Alignment and fluff I can't help you with, but what you want in terms of domains is the Strength and War domains.
The Strength domain gets you Feat of Strength—once per day, for one round, you have a bonus to your strength rolls equal to your cleric level. Very quickly this becomes substantial, but even better is the domain spell—Enlarge Person. The best way to grapple and do unarmed damage is by getting big. You also quickly get Bull's Strength, which makes you stronger for a short period of time. Given a chance in a fight, cast both of these on yourself, then go to town. The War domain is useful to you for the Weapon Focus with your deity's preferred weapon. I don't think any of the normal gods favor unarmed attacks or grapples, so this is probably only an option if you get to make up your own god. Then, it's a free +1 to either grappling or punching, your choice.
This is a basic starting point for you. Browse through the Handbook to see if anything catches your eye (though note that they use a lot of stuff from other books, which may or may not be allowed at your table). If it turns out you can't rebuild the character but have to play with what you've got (and note again that I would politely argue your case here), give us some more details on what character you have and we'll see what we can do to repair them.