Shifting quirky?

I have a Sora front der and Tiagra in the back, triple chain. Under stress, up hills mostly my shifting isn't as smooth as I'd like. It is not terrible but there is some skipping of a gear and a clunk that dosen't sound to good. Is this just some thing a good adjustment will fix or would I be wise to upgrade the Sora up from to a 105. I have Sora STI shifters on the brakes. I'm a newbe be here and don't want to get into upgrading the rear and the shifter, but I figured for 30 bucks the front Sora would be something I wouldn't mind upgrading. It's not a terrible situation for me as I ride to keep in shape and only do 120 miles a week, to supplement my running. Kness are starting to show the wear and tear of years of running and cycling is a great addition to my fitness program plus it is a lot of fun. Anyway and help or comments would be appriciated. Thanks. In case it matter my bike is a Specialized Allez. 24 gears.
Thanks again.