What items provide quick heals in dota 2?
To me, this sounds like you're taking unnecessary creep damage. The only time you should take creep damage is when you're harassing an enemy, and even then you want to make sure you take less damage then they do! Make sure you're not doing that and actually warrant heals because these items are all pricey if you don't actually need them! Here are the items that can heal you in the game, excluding the Bottle that you're already aware of (and is more often picked up for mana restoration than for healing).
(source: cursecdn.com) - Tango is a consumable you buy from the main shop with 125 gold. It gives you 4 charges that can be used on a tree to heal you for 115 hp over 16 seconds.
(source: cursecdn.com) - Healing Slave can be bought for 115 gold from the main shop. If consumed it will heal you for 400 hp over 10 seconds. If you receive damage during this time the effect will be stopped.
(source: cursecdn.com) / 
(source: cursecdn.com) - Magic Stick and Magic Wand are extremely cost efficient items that gain a charge anytime an enemy casts a spell near you. You can activate the item to restore 15 health and 15 mana per charge. This item is also great for making use of Iron Branches that you should buy at the beginning of almost every game.
(source: cursecdn.com) - Ring of Regen costs 350 gold and can be bought from the main shop or the side lane shop. It will increase your hp regen by 2.
(source: cursecdn.com) - Ring of Health increases your hp regen by 5. It costs 875 gold and can be bought from the secret shop or the side lane shop.
(source: cursecdn.com) - Urn of Shadows costs 875 to make and has an active that will heal an allied hero for 400 hp. The healing is interrupted if the unit takes hero or tower damage.
(source: cursecdn.com) - Tranquil Boots costs 975 to make will give you 12 hp regen while out of combat. The healing is interrupted for 13 seconds if the hero attacks or is attacked.
(source: cursecdn.com) - Mekansm is more expensive at 2306 but is a great item for support heroes to make as it heals all allies in a nearby radius for 250 hp instantly. This makes it a great teamfight item and every team should have one.
There is 1 more very important item that Lustin didn't mention, and that is the magic stick.
Early on in the game, this is a great way to get that small burst of health or mana that can often save you from death or provide the ability to get that crucial early kill.
And as you get more money, you can upgrade it into a magic wand for even greater effectiveness.
If you are constantly running out of life/mana, then there are a few things you can do to improve that situation.
- Buy a Stout Shield. This protects you quite a bit from ranged harass and can greatly boost your survivability.
- Watch your positioning. Don't attack an enemy hero when you are surrounded by creeps as they'll immediately target you. Don't hang around in the middle of the creep line either. Only go in for denies or last hits.
- Don't spam your skills too much unless you'll either a) get a hero kill b) prevent a hero death or c) keep yourself in the lane longer (do this sparingly). Mana management is very important early on, don't waste it on creeps.
- Get some branches. The boost in mana, health, and damage is quite significant early on in the game, and branches will be required to make that magic wand anyway.