Hi Stacy,
I also just bought a 2003 HCH but with Alot more miles. I bought my car Knowing or thinking i had a tranny problem but i was getting the car real cheap to make a long story short my tranny problem was not a problem it was my EGR so I was lucky. I only found this problem by reading thease forums they are great and filled with info. In my opinion the EGR valve will go bad soon or later. if you replace it yourself cost will be around $160.00 by the dealer under $300.00 so if you can get them to replace it before you buy it GREAT,if not well you know about what it will cost. Oil cgange and tranny fluid change very simple. under the car you will see a large plastic shield covering the entire bottom of the engine and tranny little plastic clips hold it on pull the center of each clip down about 1/8 inch and wiggle the clip and they come right out. once the cover is removed look straigt up and you will see the oil filter. on the passenger side you will find the oil drain bolt and the driver side you will see the tranny drain plug you will need a 3/8 Inch drive ratchet for the tranny drain you will see why the tranny drain plug has a square hole for the ratchet to fit right in, no socket needed. use 4 quarts 0W20 oil for the engine, Buy Honda CVT fluid for the tranny you will need to buy 4 Quarts you will only use 3.5 Quarts new washers for each drain plug should be used. since you are buying a used car you do not know for sure that all was done so do it when you buy your car and you know you are good to go. As for the battery's i was told they are maintenance free nothing to do. any particular questions you might have Just ask here there are alot of really helpful people here.
Good luck with your car.