LexuSY, you asked for opinions and you gonna get lots of them.
1. the air filter is a piece of cake. $12 part and will take less than 5 minutes to put it in. I can even talk you through it over the phone.
2. The bulb is easy too, it's just getting to it that is a little pain. Search, as there are several threads and I remember one with pictures.
3. How much oil are you leaking. Better question is how much oil do you have to add between oil changes or ever 5000 miles? You could try a heavier oil, (10w-30) if you are running a 5w-30. Just remember, leaks eventually get bigger.
4. Lastly, your engine is a non-interference engine. If the timing belt breaks while you are driving, the engine just dies and there is very minimal damage if any at all to the internal workings of the engine. You could just go until it breaks. I would not advise this but it does not have to be done today. The flip side to that is imagine where you could be if and when it breaks. You could be in your driveway or 50 miles up a deserted highway at 3 AM. Most dealerships prep you for the TB cause it is usually done around 90k miles. It is a big expence depending on how far you go. Meaning do you replace just the TB or while in there do the water pump, accessory belts, pulleys, cam and crank seals, tensioners, etc. Either way, shop around for this service. Look into Toyota dealerships as well as respected independent shops, prices will vary dramatically. Remember, cheapest is not always best and neither is the most expensive.
steviej